I bought a round of drinks the other night and it cost me $190 ( around $44 a drink). Also dropped 8k on a table the other night. Shit ain't cheap in Vegas.
I'm not an every week club goer anymore like my 18-21 phase. I have my spurts where I go hard, but other than that, maybe only go twiee a month on average
As for the purpose. For me its a combination of things;
1 - High energy environment where you can have fun socially with friends
2 - Easy way to fuck a lot of girls
3 - Good music - had a 15k table at Omnia for Martin Garrix a few weeks back
4 - Networking for business events. Made a lot of money and connections from nightclubs after industry conferences