The benefits of meditation are many and various, so I won't try and detail them all here. What I'll do instead is lay out all the benefits that you are likely to encounter just by focussing on your breath (or something else) for at least 10 minutes a day.
1) Relaxation
Sometimes you might hear mindfulness teachers say that meditation isn't about relaxation. That's quite a helpful thing to say, because in a way meditation isn't about relaxation, and if you think it is about relaxation, then you might start making a big effort to relax, and finding that you can't relax (because making a big effort is the opposite of relaxation), and then getting frustrated.
But in fact, relaxation is something that does tend to come with meditation, and is profoundly beneficial. Don't underestimate how much of your suffering is caused by agitation, and how much better it might feel to relax a bit.
2) Mindfulness
By this I mean a basic awareness of what's happening here and now, as opposed to being lost in thought. Any meditation practice will promote this, because in order to meditate, you have to...remember that you're supposed to be meditating. Again and again, you'll get distracted by your thoughts, and then you'll notice, and re-engage with the meditation. And in doing that, you'll get better at noticing when you're lost in thought, so that it happens more frequently. And that will also happen in the rest of your day, so that instead of being lost in thought for most of your day, you'll regularly notice that you're lost in thought, and reconnect with the here-and-now. And the benefits are enormous.
3) Focussed attention
If you are trying to focus on the breath, you are trying to focus on one thing, and so you might get better at doing that. So if, for instance, you find that you can't get from one end of a podcast to the other without losing the thread, then with regular meditation upon the breath (or some other object of attention), you might find that your concentration improves.
4) Knowing your mind
When you try to meditate on the breath, you will be distracted again and again by thoughts, but you'll notice that that's happened. And when you notice that your mind has wandered, you'll probably notice where it went. And if you do this again and again, you'll start to notice the habitual patterns in your thoughts. You might realise that you spend a lot of time, for example, criticising yourself, or fantasising about how you want things to be, or picking over bad memories. You'll get to know your mind better.
5) Seeing thoughts as thoughts
This is one of the most profound effects of meditation: seeing that thoughts aren't inarguable truths, or commands that you have to follow, but rather are just...thoughts. And it can start very early in your practice. As you notice again and again that you've been distracted by thoughts, you might start to notice just how insubstantial thoughts are, how relentlessly they keep on coming, and that you are neither choosing them nor able to control them. They start to seem less like you talking to yourself, and more like words and pictures thrown up by your mind, to which you needn't give too much weight.
6) Sitting with feelings
And just as you'll learn to see your thoughts come and go in meditation, so too with your feelings: if you meditate daily, you'll find yourself meditating in a range of emotional states. And when you're meditating, unlike the rest of the time, there will be no getting away from your feelings - you can't surf the internet, or have something to eat, or snap at someone. Instead, you'll have to sit there and just...feel your feelings. And in doing that, you might start to learn that your painful feelings aren't really so bad. It won't kill you to sit with them, they don't last forever, and they're not the unmanageable blobs that they often appear to be. Rather, they are made up of thoughts and sensations, none of which are that bad in themselves. So maybe you can let them come and go without needing to anything about them, in meditation and in the rest of your life. And if you can do that, then you'll be much freer to do what you really want to, instead of being bounced around by your emotions.
7) Patience, persistence, and gentleness
Whenever you are meditating, you are not only working on the meditation technique; you're also working on your attitude. If you meditate in a self-critical, driven way, then you are training yourself to do that in other situations as well. And if you can learn to meditate in a patient, persistent, gentle way, then you will be training yourself to have that attitude in other situations as well. And you will develop this kind of attitude, if you stick with your meditation practice, because it's the only attitude that works. If you meditate in a driven, self-critical way, getting angry with yourself every time your mind wanders, then you will make the whole experience so unpleasant for yourself that you're liable to give up. If you want to keep on going, then you'll need to learn gentleness, patience, and persistence.
And those are the benefits that you can expect from the simple practice of focussing on the breath.