It's not a question whether or not it's useful, it's a question of whether or not it's worth dealing with lower healing throughput and trashy cooldowns for something as marginal as a slight TP reduction that becomes a complete non-point since there's only a handful of fights where TP management becomes a big issue; or a damage reduction that you can't summon when needed in a game that's all about premeditated damage. It is illusion of strategy if survivability increase is 0.01%.
Either make the cards so good and so controllable they actually make a difference (as opposed to "huh, that's cool" format they have now) or revamp the baseline healing ability to the point it doesn't become a burden.
