Hapless Researcher

The sacrifice clause is the entire trick: a 1/1 that buys time on the board, then converts itself into a loot when the body has outlived its usefulness. The card disadvantage is real, not avoided. You spend a card to cast it, and the ability replaces itself in hand while consuming the creature, so the net is still down a card the way any rummaging effect is. What the design buys is timing and a temporary body. The loot is deferred, paid for by a creature that already did a turn of work blocking, and the draw-then-discard ordering means the discard is yours to aim: you bin the card you want in the graveyard after seeing your draw, rather than blindly digging past it. That ordering is the point. Decks built around what ends up in the yard get a creature that pitches a fatty or a flashback spell on demand, feeds a delve cost, or stocks a self-mill engine, with an early blocker thrown in before any of that happens. The sacrifice is the switch between the two modes: warm body now, graveyard fuel and filtering later, on a clock you control. It is small, honest utility built on the recognition that a one-mana 1/1 is rarely the card you most want to keep, so it lets you decide exactly when to cash it in.