Every time you take a photo it captures that moment in time. Your parents probably all have hundreds of albums of pictures from when you were younger. Those are memories that are in the past now, and all you have are the photos to be able to reminisce on the simpler times because now you are older and there are a lot more responsibilities that come with that. And there are moments in your life you aren't ever going to want to forget like prom, graduating high school/college, getting married if you choose that, and having kids if you want them. There are so many milestones that you are gonna wanna look back on that without pictures or videos you won't be able to because they will be in the past and as much as we want there to be there is no such thing as time travel. After the moment has passed there is no way of getting it back.
They hold such precious memories that otherwise would be long gone.
The time your sister and you had matching Halloween costumes or the time you had cake all over your face on your first birthday. There are memories that pictures give you that you most likely don't remember at all. They capture moments in time that could get lost forever.
They are a great decoration for your home.
They hold happy times that you can display in a nice frame on your mantle, your wall, on top of a piece of furniture. They are also a way for you or your kids to see a progression of your life. Be able to look back on them and remember things that you might have forgotten, not to mention be able to see what life was like when you were a baby because of the likelihood that you remember things that far in the past isn't very likely.
It also lets you take a glimpse into your families history.
You can see what life was like for your grandparents, or your parents. See what they lived like and how their childhood was. It's also a good way to be able to see the resemblance, who you like more and who you got certain features from. You never know what you will come across, things that you didn't even know happened to your family or experiences that they had that you never knew even existed.
Don't take a picture for granted, one day you will be happy that you have that picture. 20 years from now you will be able to reminisce on all the great times you had in your life. You can always take a picture if you want to, now that almost every phone has a camera on it. Take advantage of that, but don't always have your phone out taking pictures because you have to live in the moment too. But it doesn't hurt to take a couple of pictures here and there when you are living your life.