When the timing is right, it can also sacrifice itself to protect your board, so its both a strong deterrent and a safety valve
Having reach, trample, and protection against multicolor means that the card can be a brick wall to many threats in many different formats
Legendary Creature - Human Druid Mystic Remora Cumulative upkeep (At the beginning of your upkeep, put an age counter on this permanent, then sacrifice it unless you pay its upkeep cost for each age counter on it.) Whenever an opponent casts a noncreature spell, you may draw a card unless that player pays
In many decks, they end up being the anchor of the strategy, whether thats reanimating creatures, looping spells, or enabling anything from cost reduction to card draw