They reduce condition and authenticity risk, but still verify the cert number against the grading companys database and check the slab in close-up photos, as misleading titles and slab swaps do happen.
This Supporter works akin to a Focus Sash from the mainline games but in this case, it prevents the said mons from getting KOd by preserving 10 HP
There are of course some fantastic ways to play this and have it be genuinely powerful, mostly involving graveyard synergy or I win combos
However, the abilities make this card stand out
Overall, the deck looks like it will be really fun to play with casually , but it's a little one-dimensional, and it wouldn't take much for your plans to fall apart, especially if your opponents target your graveyard