Think of how Bitshares is governed by voting for witnesses, committee members, worker proposals. Now what if you wanted to ipo on the dex but needed the ability for voting shares for the same reasons? Mostly picking a board of directors and/or voting on their proposals.
Almost all publicly traded companies have voting and non voting shares, sometimes referred to as class A and class B shares.
UIA voting opens the dex to a whole new class of companies.