If that's a clever Labour move, I'd hate to see a bad one! It's faltered and achieved nothing that I can see. And Corbyn is scared of a vote of no confidence in the government, because if, as is likely, it fails, Labour is committed to pressing for a second referendum. Corbyn doesn't want this because (a) he's essentially Eurosceptic and (b) he'll alienate a lot of Labour voters in the North that voted Leave. So stalemate at present, meanwhile the government prepares for a managed move to WTO which has to be the right solution imo.
The way they went about it was certainly far from smart, but I thought the idea of trying to exacerbate the splits was clever, and it did smoke out some remnant support for May from the ERG and DUP. Your analysis on why he wants to avoid the no confidence vote in the Govt is spot on imo.