For real though she’s (mostly) what I aspire to be when I am old!
I’ve only ever sold at one con before so keep this in mind, but how well an artist does depends on a lot of factors: how big the con is, how much/what you sell (fanart or original, style), how you and other artists in the con are pricing, etc etc. Depending on the con people can have really different buying habits, and con success can vary hugely between artists so it’s hard to say. As a general rule I believe that if you make good art, you can make money. But you really won’t know for yourself until you try it!
I guess to answer your question with personal exp it was profitable for me the last time I went. Travel, accommodation, and printing didn’t cost me an arm and a leg which really helped. But what I get most out of going to a con is seeing friends and nice people who like my art! (੭ु´͈ ᐜ `͈)੭ु
I call them ‘the steamies’ collectively since they’re from my Steamboy project! Also this is one of those rare times when I put effort into drawing a reply but your question was so simple that I feel a bit silly now