Third entries in each Pokemon generation usually follow the same storyline, occasionally adding new areas, new Pokemon forms and new plot points to the adventure, while combining Pokemon from the preceding two games into one cartridge
For example, Sakura-Tribe Elder's activated ability lets you put an Omnipresent Impostor onto the battlefield tapped, while Goblin Engineer's enters ability lets you put an Omnipresent Impostor into your graveyard
While Hinata busts this wide open, the more general use case is as a flexible fog or board wipe protection spell
The former for the instant speed artifact or enchantment card on top of your deck, and the latter due to the format playing into the card's upkeep check
The Phyrexian angel slotted right into the Commander format and has even seen play through a variety of competitive reanimation builds within Constructed Standard
Resplendent Marshal is an example of a pushed constructed card for tribal synergies, and that's probably the reason why it's a mythic rare