I'm pretty early into the game as well, so I almost didn't say anything. But even if theres a charm that adds HP bars later, I would be annoyed about it. Why wait so long? I'm over 10 hours in. Why take a slot with it? I get similar annoyances about the compass, but at least that one I can understand because maybe some people like the challenge of landmark navigation using just the maps. There is a skill there, and it is part of the skillset of Exploration (a major pillar of design in any metroidvania).

The yellow tools, in general, I'm iffy about the design of. So far I only have 3: compass, more shards, and auto-collect beads. Of these, auto-beads is the most obviously useful. You need many beads, and they get lost pretty easy. Shards are super common and don't have many uses. But none of these are essential, and all of them get less useful the later into the game you get. The tradeoff is only meaningful early game, and seems to encourage a balance between memorizing the levels and grinding, neither are amazing activities.

Having the compass charm tied to ALL map markers would certainly up the utility of it, though it's gating another feature behind both a purchase and a charm. I've also only found 1 semi useful trap\red-charm so far. Maybe having more traps and skills that required shell bits would put more pressure on needing them and make the charm that gives extras more appeal for a trap-heavy play style?

Again, I grant that maybe I'm too early in the game yet, but I feel like these systems should be coming together and cohering more after a half-dozen bosses and 10 hours of play.