That's exactly it, the only reason Samsung uses SD in the States is Qualcomm's CDMA patents that mean if you want to work with Verizon
No doubt Samsung does it to save money. But they need to improve their Exynos chips. Especially if you are going to have qualcomm model and a samsung made exynos chipset.
Because it is IRL people see a difference. Its not just synthetic benchmarks. Its battery life, game FPS, video frame rates, thermal engineering (exynos runs hot) etc.
The difference is generally up to 25% better on Qualcomm.
So I dont think people are complaining just for the sake of synthetic bench marks. In some instances the differences are small like 13% in battery life IRW testing, slight differences in camera (much better this year imo), gaming definitely and for some who can pick up on it, video, not to mention the Exynos is noticeably hotter under semi prolonged use. Add it all up and its not actually that minor an IRL gripe. But what can we do, its clear Samsung wont spend the money to give europe and our tiny market equal phones, so one can either import or one can hope Samsung improves exynos dramatically.
However, one thing I have noticed this year IMHO the camera difference is MUCH less noticeable than the s10.
I think this is a pretty good run down on why things are different, what is different, IRL differences and why the images look different (although to be honest I dont see as big a difference this year)