No installs, IDE or compiler needed, so you can use it on any computer, even ChromeBooks or computers you can't install software on. Edit main.py with your favorite text editor to build your project using Python, the most popular programming language. When you plug it in, it will show up as a very small disk drive with main.py on it. The most exciting part of the Trinket M0 is that while you can use it with the Arduino IDE, it is shipped with CircuitPython on board. It's just as small, and it's easier to use, so you can do more. The Trinket M0 has swapped out the lightweight ATtiny85 for a ATSAMD21E18 powerhouse. Using the same form factor as the original ATtiny85-based Trinket with an upgrade. It's Adafruit's lowest-cost CircuitPython programmable board! Perfect for when you don't want to give up your expensive dev-board and you aren't willing to take apart the project you worked so hard to design.
Adafruit wanted to design a microcontroller board that was small enough to fit into any project, and low cost enough to use without hesitation.
The Adafruit Trinket M0 may be small, but do not be fooled by its size! It's a tiny microcontroller board, built around the Atmel ATSAMD21, a little chip with a lot of power.