In its current iteration this poll cannot replace the voting process on the wiki. The current process forces contributors to consider their reasons for abstaining or rejecting and to summarize them along with their vote. For the purposes of the proposal process this is a valuable point, because the reasons for rejecting a proposal can also be used to amend and improve its next iteration. Voting is also not anonymous.
That does not mean Discourse cannot be used to move the tagging voting process here¹ and make it more accessible, but it would need a plugin (Discourse can be extended with plugins), possibly a custom one.
1: Provided that there is enough support in the community to consider that move.