No, you didn’t do a dumb thing. But as Randy indicated, it wasn’t the optimal thing. It was better than nothing though.
Meaning your water heater was better off after your repair than before it.
Fortunately, putting in a plastic lined drain valve kit is such an easy and inexpensive fix, that I wouldn’t hesitate to recommend you do that. And while you are doing that, a curved dip tube would be a good thing to install as well.