I have a Clipper Card on my Android phone and pay for BART and SF Muni that way.
BART does now accept credit cards at the turnstiles now (I think this started 2 years ago). Agreed that it took a long while to get there, much much longer than in other places.
Personally I prefer the Clipper method, as it's generally faster to scan than a contactless credit card payment (that's going to always be the case for closed-loop payment system). I also like that BART (and Muni, Caltrain, etc.) will pay less to Visa/Mastercard/whomever in transaction fees if I use my Clipper card and periodically top it up (which, as I have my Clipper card on my phone, happens automatically if the balance ever falls below $10). Credit card tap-to-pay is a nice convenience for out-of-town visitors and for locals who rarely use transit and don't have Clipper (or who use a physical Clipper card but forgot it at home), but I don't think it's a great way to pay for transit day-to-day.
I mean it auto fills/pays from my card. It's just one extra step at setup. I agree it would be nice to just take my card at the rail, but "Shockingly outdated" seems a bit dramatic lol. It's certainly not comparable to "70s USSR" idk where that came from