Well, maybe.
Most of us use the Chinese knock-offs which are (or used to be before the plague) inexpensive and in fact, hardly more than the ATtiny chip itself, certainly cheaper than assembling all the necessary parts.
A UNO is not at all suitable for most practical applications in any case; if you need USB connection then a Nano, otherwise a Pro Mini neatly contains on a board all the basic operational parts (and a couple of unnecessary ones - the regulator and the pilot LEDs though the pin 13 LED can be useful). 