I don't lecture you on sniper rifles, you should stay away from talking bicycles. I've likely got a few more years and thousands of miles on 2 wheels than you do
And the bikes I was talking about were "typical" use. Crap is crap. It doesn't adjust well or perform or last.
If someone is commuting 15-20 miles a day regularly, you want something that isn't going to break or need constant attention. A decent used bike will handle that. A cheapo Sears special will not.