Yes this is another Arduino chip. Smaller form factor, less processor speed, less I/O pins. But yes this is an Arduino chip.
The Digispark Attiny85 is a Attiny85 chip with all the supporting components. No need to connect to Arduino to program, everything along with USB interface is included in this small compact form factor.
Although the same Arduino IDE is used to program this chip, the settings and upload process is different. See https://diyusthad.com/2021/07/digispark-attiny85.html for a complete list of proper settings and setup.
Being small, powerful, compatible and cheap, do not hesitate to use this in your next IOT protect.