Hmm, you're mentioning Pestal, but even if this costed the same as a Vampire, without upkeep and stuff, I'd still take Vampires over this
One of the main reasons being that Vampires are Legit Fractal targets, another that it heals and damages more in over
95% of the cases.
Lowering max hp isn't useful if you control the board like you do with Pestal, preventing your opponent from healing back is only of use in case they have quanta to heal themselves with
So basically the one situation where you have the quanta for this card, is the most useless one for it at the same time.