Alex,
Feel free to use a socket if you would like. I just usually don’t prefer to use sockets because they can become oxidized and add resistance to the circuit…it’s just one more questionable connection (or 14, in this case). Soldering a component to the board is usually a much better option if you know you’ll never have to replace it. The reason the uC is in a socket is because some people may want to re-flash the software and sometimes it’s easier to remove the IC to do that…otherwise that would be soldered to the board too. That is just my opinion, but you can do what you’d like.
Good luck.
-Brach