You can use your credit card to get onto the LA Metro now
LA Metro has soft-launched "Tap Plus," a system upgrade which allows you to use your credit card to buy a fare right at the fare gate. They haven't publicized this, probably because they're still making sure it works everywhere, but it worked for me this morning when I got on the train!
I am curious whether we'll stop seeing so many Tap card vending machines around the system now that Tap cards are essentially not required. I have a LOT of cards at home, some collectible, and I think I'm going to try and spend all of them down before finally leaving the Tap system. But eventually I am just gonna be using the credit card tapping function on my phone. It's way more convenient.
Anyway, if you are in LA, check your local train station. I have zero idea what the progress with this is on buses. If you want to track the status of this unannounced rollout, the LA Metro subreddit has been the best source of info for me.