It's pretty frustrating to immediately lose, and then have to undo to find out what the word was.
Not at all. Contrary to other games where undos are cheating, here they are part of the game. Without them it would be 80% luck and only 20% strategy.
> which is heavily implied
I can't find anything that implies this. It explicitly says:
> This uses undos deliberately rather than only as an emergency
while avoiding undos is mentioned at the end as "The Purist approach", which I read as slightly mocking.
I see it like a chess problem where you have to find the best sequence of moves, so you start off with an intial move, then backtrack, explore another idea, etc. Not like a chess match where of course you cannot undo any move.
What is legitimate here. You and the site why does any third party have an interest?