Combat guns and plinking guns and just having fun
I remember all of those times I spent arguing with people on gunboards about which gun was better and which guns were pieces of junk. I started out collecting many of the Soviet era military style rifles, namely the SKS rifles. There are some fun accessories from Tapco that can make even an old relic like an SKS into a more modern looking rifle, but even if it’s not an AK, you can always customize the firearm to your liking. I wouldn’t expect to use an SKS for house to house clearing, but if you got it for $200 and want to improve the fit to your liking, go right ahead.
One problem I have found with many of the semi-autos I owned was that the length of pull on the guns was very short. This was not something I go too worked up about with the plinking firearms I owned, but for a primary weapon, the rifle stocks you use on them should fit you like a glove. Customizing a firearm to fit you is an important step in learning how to effectively use a firearm. I have learned that the hard way with various rifle scopes that ended up putting a ring around my eye because the stock was so short, I forgot to adjust my bean and got a good thunk. There is nothing wrong with changing the butt pad on any gun you own to fit you. Just be aware that when you are wearing a heavy coat or winter clothing that LOP might need to be shorter, so don’t modify your stocks too much, and think about an adjusteable stock for just that purpose.