If you really must just to get through the next couple of days and this is your only transportation then sure, it'll work. This is the rear brake, after all, so it's not like it's your main brake. The limitations that the others have warned about are very real. Just don't be pulling on that lever like you're trying to stop the world in its orbit and you'll be OK. So no panic stops.

In other words if you ride in nasty traffic that can be trusted to do the unexpected in its attempts to prune you from this existence then I think I'd let the bike sit for another day. But if you commute on pathways and have more control over your reactions then it would work just fine.