Teensies are very much overkill for a lot of projects. I have gathered a decent amount of random microcontroller boards now and it's just a lot of fun to make them do random things.
I have some arduino nano knockoffs to do the really simple pin toggle things, some ESP8266 modules for when I need to do wifi enabled things. A few wiznet modules if I need to add ethernet to any module and the new raspberry pi pico boards are amazing if you need more performance and a really nice SDK.
The Teensy is a bit more expensive than those but you get almost an order of magnitude more performance for that cost, the perfect product between the other MCUs and just putting a linux enabled SBC in your project
I have some arduino nano knockoffs to do the really simple pin toggle things, some ESP8266 modules for when I need to do wifi enabled things. A few wiznet modules if I need to add ethernet to any module and the new raspberry pi pico boards are amazing if you need more performance and a really nice SDK.
The Teensy is a bit more expensive than those but you get almost an order of magnitude more performance for that cost, the perfect product between the other MCUs and just putting a linux enabled SBC in your project