The thing about cheap knock-offs is that the quality is unpredictable. Something like the camera maybe fine if it uses all the same type components. On other items contain more chips you often will run into compatibility issues, like arduinios versus knockoffs. The knock off arduinos use a ch340 type chip vs. a FDTL. Same issue with some adapters like TTL to USB. some of these chips won't work easy with the Pi and often require special drivers for windows.
One thing I really like about ordering from companies like pimoroni is their extreme customer satisfaction goal. when I had found a hardware fault they not only made it right but went above and beyond for me. So if I spend a few more dollars on a quality product from a reliable distributor that also is a mammoth supporter of the community around these I feel its a win for everyone.
I do buy cheap items on ebay too however. I use quality products for my actual prototype temporary build for their reliability. Then , if my project actually used in real world, I may assemble with cheaper knock-offs for testing once I know how it should run. I do this mostly with arduino items like the micro and such. I could see the value in that when something will be weathered outside, launched, or possibly be destroyed in real world testing, but often my finalized creation will use the quality parts.
When learning to use new hardware the greatest benefit is the reliability and being able to follow others' works as guides knowing there is less variables there for error.