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.
Although it probably doesn’t matter in this case, it’s worth noting that your hub/dock and all connected accessories use power from your charger too. For example my laptop reports my 65w charger as 45w with my USB-C dock in between.
In your case this could mean your deck only getting 30W, which would be fine for less demanding games, but with a full load could mean barely charging / not charging at all.