Thanks for checking out the game!
Task resolution has a set distribution of target numbers that doesn't change. Death saves are the only "stat" that increases over the course of the game, basically a proxy for character level, increasing from 1.
Rolling low for task resolution doesn't feel right. So it's a choice between having both mechanics be roll-high and needing to translate from character level to the death save mechanic (or having death saves start at 6 and count down as you advance, which also feels weird). But also, personally, I like games that make death saves feel special in some way, and I like the simplicity of the easily readable (emphasizing its low) chance of save afforded by this method.