Don't get me wrong, I've bought my fair share of stuff from local marketplaces (FB etc). Just a bit hesitant about electronics personally.
Oh no it's not like that. Refurbs run the gamut from cleanish-used quality to units completely rebuilt with new parts. On average though, you are going to get something closer to the new side. Plus, they are qc'd on an individual basis so that can be better than brand new, which can be done in batches.
Give it a shot sometime you might be surprised. You generally won't get the retail packaging, so be warned of that. If I was getting a steam deck I'd go straight for the refurbs because I think valve would do at least a decent job of it.