With the countdown, you more want to care about the high level stuff: Keep your brain agile enough to get the next one, figure out more general patterns, ensure you "cover" the promising patterns, notice tough spots (with tons of patterns) where you you'll need to lock in. That stuff is more fun to focus on than speed.
Everyone wants to fail less, sure. It's not surprising people's feedback focuses on the mechanic that made you fail! That doesn't mean changing that bit will make the game more fun.
The timer doesn’t have to be visible at all until the end.
> Everyone wants to fail less, sure.
It has nothing to do with not wanting to fail. Sometimes people just want to chill a bit or kill a few minutes with a simple word puzzle that engages your game without being stressful. This game doesn’t even let you repeat the challenges you took, so to play it you always have to be highly engaged. That’s fine for some games, but not every game needs to be like that, and this one doesn’t.
No one’s asking timer mode to go away, or even become the default, just to have the alternative option.