Looking at the charging preferences of the Steam Deck, which from my research wants 45W at 15v/3A, it looks like the larger model should work just fine. And with it being $15 USD / $18 CAD this could be an incredible bargain.
It’s so new though I can’t find any info on it being used with a Steam Deck. I’ll definitely be grabbing one to try, as it would be perfect for my USB hub that sits by the TV.
The only limitation that I ever saw was - if you’re using a USB-C to USB-A cable to connect to your charger, the deck will say “charging slowly” while pulling absolutely nothing. It will only pull USB-C PD power. If you have a huge battery bank that can put out tons of 9v power on a quickcharge A socket, too bad.
USB-A, per the specification, is only supposed to provide 5V max. Qualcomm Quickcharge violates the USB-A specification, so only other devices that are designed to violate the specification and thus be compatible with QC will charge faster.