Other banks don't offer that (top ups via card), and I don't think it's something you should expect of a bank account - it was always a stop-gap. If you're using it for spending regularly and don't want to switch, just set up a standing order for a bit of money each week/month to try it out. I think as they want to become a bank this is part of that process - their focus needs to be on those who use it as their main account.

Personally I switched almost a year ago (when they introduced CA), and am happy with that choice so far - kept my old bank just in case but haven't needed it. Re outages many banks have had major outages recently, far more than Monzo... They had a few glitches early on (late last year), but I'm fairly confident of their ability to scale now.