That card also goes to the graveyard since you discard it, which is sometimes a slick combo play with the reanimation targets like Malboro
Right now Im playing a playset even in Hammer Time, but I recollect playing this card in a lot of different archetypes, from UB control to Ad Nauseam, from Goblins to even Sultai Urza
Its classic and good in a multitude of formats, and I think its perfectly balanced
While Tocasia's Welcome is far from being our mighty green artifact, it can still provide you with enough card draw through the course of a game to justify running it, especially if you use creatures with flash like Cathar Commando that can be played on your opponents turn to draw a card
The Replenish deck could sit back, lose card advantage turn after turn with Attunement, and still come out and win at its leisure as Parallax Wave, Opalescence, Seal of Cleansing, and other enchantments all entered play at the same time