I’ve released over 20 apps on the App Store, since 2012, but none have taken off. TBPH, I haven’t really tried. My free Bluetooth sniffer apps seem to be fairly popular, but I am not really in a hurry to start making a ton of money. I don’t really need it, and I mostly release stuff to stay in practice. I think I’m down to only three or four apps, now: https://littlegreenviper.com/AppDocs/
You would think so, but I keep not using it in my projects.
It's a very "in your face" UI element. It's the star of the show, and I have a personal philosophy that UI should remain in the background, as much as possible.
This is why waitstaff at restaurants often wear black uniforms.
The checkbox widget[0] has actually been far more useful to me. I use that all over the place (In its SFSymbols form, so it looks like a Mac checkbox). I'm not a fan of Apple's UISwitch widget.
I will, eventually, do SwiftUI versions of these widgets, but I'm not in a hurry.