Greatest danger would be waiting too long, watching the toxic Tory deal pass before a general election, waved through with Labour votes & lukewarm tutt tutting but no meaningful action from Corbyn. The failure of Labour leadership has been staggering
I believe there was a growing appetite for a PV in this parliament. This push for a GE suppresses that. The big issue, though, is it requires serious hubris to believe this is a route to one. Reality is it could easily facilitate a no deal Brexit if not now then in Dec. 2020