Hmm, I'll be honest, Temmie Armor isn't all that super-fantastic. It's good, but it's not like it makes the game THAT easy.

Spoiler:
And it's ironic, because I was actually able to get through Photoshop Flowey in one go before when I didn't have it, and now that I do have it and know what to expect, I just got nailed twice (I honestly think armor doesn't make a difference during that battle). And that sucks because I was on a deathless streak before that happened. XP