I kinda like when "hard mode" makes you have to come up with a possible word even if it seems impossible to think of one, which can be a satisfying puzzle, not having the restriction makes it easy to think "okay screw it, I'm going to spend a guess to search for letters".
It's in an important sense actually easier! Sure, good play results in more guesses than in not-hard-mode, but that would be like saying a 100m sprint is easier than a 2-mile race because the latter takes longer. The more interesting measure of difficulty is how hard it is play optimally. And since the search space for not-hard-mode is bigger, I'm pretty sure it's harder.
But more importantly, hard mode is also less fun, and this thread demonstrates exactly why: the creative aspect is coming up with le mot juste for quickly honing in on the right answer. Hard mode takes away your tools to do that and sometimes even results in a thoughtless guessing game.