Comparing RTL8192CU and RTL8192EU models highlights differences in design and features.
Comparing RTL8192CU and RTL8192EU models highlights differences in design and features.
Your perspective is based on similar chips, which are generally budget models. Many wireless devices use varying frequency options depending on location. The CU model seems to work on channel 14 (2.4835 GHz), whereas the EU version doesn’t support that frequency there because it’s not allowed in that area.
Others suggest there might be almost no distinction aside from internal firmware that dictates available channels. Even then, it wouldn't surprise me if these are just marketing codes, since the region is typically managed through software. I've purchased several WiFi adapters from China, and there hasn't been any clear difference in performance, likely because they're all produced there anyway.