You had one job!

Actually, Batman did for a time.

Yeah back in Detective comics he had a revolver. But not a rifle like those

No, not like those. But a gun none the less

What would superman even use a gun for. His eyes shoot lasers

Well, In the comic's Lex Luther managed to gain superman's powers for 24-hours.
One of those guns is know as the gravity gun, he used it on Luther to keep him in place and speed up his time. In the end Luther only had 20 minutes with superman's powers.

He couldn't always do that. Superman put mental limiters on his poweres when he was young and spends his life rediscovering them. Depending on the timeline you look at, that is one of the last powers he gets. Also, it drains his power very quickly.

Alright riddle me this what's the armor in corner for