Wow, even a $200 GPU has a proper fan instead of a blower. Please AMD, just ditch the reference vacuum cleaners already.
If you want open coolers, buy the damn partner cards with open coolers. Reference coolers are about compatibility with
more than just the well-ventilated enthusiast gaming tower.
Dumping 100W of waste heat back into the case is probably acceptable for the vast majority of case scenarios, but dumping 225W of waste heat into the case is not. That's
probably why this is an open cooler. It's also not strictly a reference design - only an OEM one that happens to be the OEM that also builds many of AMD's other reference boards. You can bet that the RadeonPro variants of these will be either fully or partly exhausting because those
will be true reference designs.
I often need to spec a blower cooler and it's frustrating how few good ones there are. You may not like them and they me be louder than coolers that dump all their heat back into the case, but they are an industry necessity for OEMs, SFF builders, HTPC builders, GPU farms, Quiet PC enthusiasts, and probably more categories that I haven't even thought of.
My big old gaming tower with an excess of empty space and airflow has no problem with cooling, so yeah I'd definitely pick an open cooler. Please don't hate on the exhausting blower when it's not designed for only your use case. Some of us really really need them and builds simply wouldn't be possible without them.