With "clean as they are" I meant of course the topology. And with good topology you could actually sell models in one of those 3d market shops. But I understand very well if you don't want to.
About product shots: Actually catalogs are still printed, not so much anymore but still in use. Sometimes because of the target group, sometimes as inserts in newspapers and sometimes for no other reason than that the people in charge are still a bit old-fashioned. But the pictures you need of course in even better quality for websites and shops and for advertisements. That's quite often 3d, not just because the product isn't even produced yet, but because it looks better than the real thing. Also, as soon as the model is finished (often imported from CAD, and then (not always) retopologized, altered, remodeled or partly replaced), it can be cheaper in the long run. Good photographers are expensive, and as soon as you have the model it can be rendered in different environments, different angles, etc. (and sometimes you can get 3d "art" quite cheap. There are platforms, indian 3d artists who work for a dime, and so on). Also, you can have the thing in any color variations you want, can use it for 3d view in shops and more, can have different sizes. In some cases it started life as 3d model in some dcc app anyways (the product design) and has just to be rendered.
If you look at web-shops, advertisements, or any webpage of a manufacturer you'll see a lot of 3d.
While the pohtographs are usually heavily edited to eliminate blemishes, too clean 3d with simple materials looks to unreal even for such purposes. It's bad if every possible customer sees in an instant that it isn't real. In a few cases 3d artists get away with a lot (it still looks better than the original, though), but mostly it's nothing I would really call a flaw. It's subtle irregularities in the coloring of the metal for example, a touch of variation in the roughness of the plastic. It's not obvious and certainly mustn't stand out. If you almost can't see it, it still makes a difference and results in a seemingly real (or at least halfway believable) picture.
(on the other hand, it's sometimes astonishing how often bad photos or bad 3d actually are used. There are websites dedicated to photoshop fails which sometimes are quite funny).