Weeell...
Got into this nice "clicker". The music is enchanting :) and that made me want to dwelve a little bit more into it.
The NPCs telling me that "monsters will soon fight back" made me upgrade my defence. I got a little suspicious, because I dealt the same damage to ennemies with 1, 2 or 5 defense. I still did it.
I encountered the first ennemy with "1" attack while I had 2 defense points. It dealt damage. The next one killed me with the same stats, "1" attack for ennemy and 2 defense for me. Soooo... what's the point ?