Not really, back in 2007 many of my mates had the phat PS3, bought in Portugal, with full support for PS2 games hardware-wise.
There's 2 models of the Phat, the one that does software emulation (the Phat PS3 with 2 USB ports) and the other with hardware emulation (4 USB ports).
Like I said, if you're looking to buy an early model, you know damn well what you're getting and how well it does for your best interests.
I also replaced the thermal paste of one of my friends's model and the EmotionEngine chipset was right there, proving it wasn't software based but hardware.
Limited compatibility has nothing to do with the fact that it plays on hardware, of course some games are gonna have their share of troubles perhaps because its not being ran on an actual PS2 console
2 USB ports were later models such as the 40GB which didn't officially support PS2 playback in any way. (Unless you buy officially licensed PS2 games from PSN).
There were two kinds, hardware based and software based. Japan and America had the hardware based models and the EU had software based. It's best for you to research within the support links on the official Sony website so you don't get confused. The link I sent earlier shows which EU models were officially able to play PS2 games. Japan and American can be found by a quick google.
https://support.us.playstation.com/...ne-and-PlayStation-2-Games-on-a-PlayStation-3