This is something I see often. People who have never actually used a DEX talking about how there is too low volume or it is too risky to trade with other people. Meanwhile I've been using DEXs exclusively for years and have never once been scammed and never once struggled to find a trading partner (although maybe that's because I only trade in fiat/Bitcoin/Monero and not a bunch of useless shitcoins).

If you are day trading to try to make profits, then sure, a centralized exchange is probably going to be your only option. But for everyone else, there is no good reason to use a centralized exchange. As you say, you don't need bitcoin now, and a DEX will work just fine. You will spend just as long (if not longer) waiting for your fiat deposit to be credited by a centralized exchange than you will waiting for the same fiat deposit to be confirmed by a peer-to-peer trading partner.