Learning an actual machine language is definitely harder, all of these games use extremely limited instruction sets and/or simplified operating conditions.
As for more beneficial, I'm sure learning a real practical machine language is more beneficial. However you can definitely draw some of the same lessons out of these games and depending on you, might have a lot more fun and chances of actually going through with playing these games.
You just reminded me that I wrote a stack language for DCPU16 back in the frenzy. It gave me an excuse to learn the IronMeta parser generator, which is an implementation of OMeta. Unfortunately I kept it on Codeplex and never bothered to move it since the entire idea was dead by that time.
As for more beneficial, I'm sure learning a real practical machine language is more beneficial. However you can definitely draw some of the same lessons out of these games and depending on you, might have a lot more fun and chances of actually going through with playing these games.