The master rigger at my DZ recently took an inch off my closing loop, and I'm no longer strong enough to close my rig with just a pull up cord (by comparison, it's easy for him - but he's closed thousands of rigs and I've probably packed 60 times so far. I'm a baby bird / A license).
A power tool will get it done, but the Puca tool is WAY more effective for me. I'm sure as my hands get stronger I'll be able to pack without it, but for now, it's invaluable.