-
You are right, plastering onto wooden studs is not advisable. They move a bit being wood and there's a chance that it may cause the plaster to pop out in chunks or crack.
If you were posting this as an example of professional work you'd had carried out we would all support you in recovering the money or finding a new plasterer! but it's your place and you're learning a new skill so fair play.
I thought Stevie Wonder had retired!
Looks pretty straight, not bad for a first attempt.