The fact that hardly any Duel Links players see the potential in Rescue Rabbit, based both on how powerful it was in the TCG, and how its ability to establish rapid consistent board control even on turn one is... a real testament to how konami has trained duel link players to react to cards in a vacuum.
It's a free +1 that thins your deck by 2 cards. Only in duel links could people question if that's good, because it didn't come prepackaged with a rabbit themed boss monster.
Remember the Infernity hype? They were great in the TCG but they struggled in DL. This format is different. And rescue rabbit has some serious issues in DL
And then what? You brought two vanillas to your field for what?
Well, you most likely will bring out an Xyz, sure, but what Xyz? There's not much good generic 2 material Xyz at the moment.
Rescue Rabbit's worth is not solely determined by the fact that it thins your deck, but also by what can you do with the summoned monsters. And right now, it's not doing much for the latter.