Even though skins in CSGO are pretty useless (unless you count the design value), you are still going to get them through various weapon case drops. Sure, you can just drop them again, but how about try and get some use from them?
You can do that by betting the unneeded skins in various platforms. Of course, to do that, you have to find some reliable place to bet in. you can do that by first reading some reviews about the website, so you could see whether it is a credible bet site or not.
When you pick the website you want to bet in, you should read more about the teams that participate in professional matches. It would be best if you could watch a few matches so you could get a better feeling how the teams are playing together, to better know their strategies.
After learning more about CSGO professional teams, you can start betting on the possible winner. If it so happens that you run out of possible money to deposit, you can try to get some free coins or affiliate codes that will give you more money to bet with.
So in the end, you can use the skins to get more money than you had before. That is pretty convenient, especially if you are good at guessing the end of professional matches.