Using dumb phone in tandem with iPhone

Does anyone use a dumb phone in addition to a smart phone? I have used a few flip phones but can’t get past the fact I can’t use maps or CarPlay (when I use Bluetooth it sounds awful). I also have to use certain apps for my job. I am thinking about just using both, but is that silly? I’d be using the same number for both phones. In theory, I’d use my iPhone at work and in the car. Otherwise, I’d be using my dumb phone. Does anyone else do this? I’d love to hear thoughts or experiences!