My recent experience of Union meetings (the CGIL in Italy with a high % of attendance, I've yet to attend an NUT meeting here) is of turgid droning that people sit through (albeit chatting, doodling, fiddling with phones etc.) under duress. They (we) know it's important, but detest the dull proceduralism that inhibits any sort of participatory engagement, or organic discussion.
Whilst this may, in part, be shaped by the Union's role in negotiating equally turgid contractural and legal stuff, a formation like Left Unity does not play this role.
I'd argue that workplace organisation shouldn't be bound to thus role either, but that's a harder fish to fry.
A new formation, who's initial momentum and appeal came from bypassing old structures and a focus on using social media to enable/empower participation "from below", has absolutely no need to ape TU procedure.
That it does is at best lazy. At worst cynical power grabbing manoeuvres.
But, yeah, I might be wrong. People might really dig this shit.