Not only do you keep the monster you summon, but you also gain a negate and a battle position shift effect, making Gallant Thief a formidable threat
Thunder Dragon Fusion : Fusion summon a Thunder fusion monster from your extra deck by shuffling the fusion material from your banished cards, GY, or your field into your deck
On the other hand, I dont think argument is as relevant when you consider that Commander, at its heart, is a casual and social format
Given that Atraxa herself, the Phyrexian angel horror and one of the most popular commanders, is also arguably one of the most popular cards that uses the proliferate ability, its no surprise that Atraxas Skitterfang is primed for combos using the ability
With their friends and comrades watching over them, Crysta disappeared into the light along with Lapis
And it turns things like Level Ball and Revive (ROS 88/108) into one-for-one draw cards, as well