Why would I want an authentic FTDI chip for technical reasons?
With the FTDI-supplied silicon containing several bugs already, my wild guess is that cheap knockoffs are really bug-ridden.
The likelihood that you encounter such a bug when really just using the thing to run a relatively low-speed UART is pretty much 0.
So, as said, FTDI's products' popularity among users of USB-to-serial adapters is probably mostly due to the fact that they write usable drivers. You want these drivers, you need to buy the original device (Plagiarism aside).
That's a pretty good reason, actually. If your software depends on the particular driver, you depend on the particular device. I don't know if that's the case here, or whether the BTECH software simply uses the Windows COM: port emulation that FTDI's own driver, but every other (legitimate) USB-to-serial bridge manufacturer's driver offer.
The fact that there are knock-offs that work with the same driver puts someone in a position of breaking a driver license – don't know if that's you, the knock-off cable manufacturer or the software supplier. Not a lawyer.
The point that FTDI (catastrophically) tried to make is that, you know, they developed something and now there's freeloader silicon manufacturers that just live off that, and that is bad for the original developer, and it's potentially bad for reliability.
Can't say I agree the slightest with how they went about telling the world, but I can understand that there's a slight chance that if you're using someone else's driver for your device, it's likely that something might go wrong with your device at some point, because the people designing the driver aren't the ones who designed the silicon.
By the way, if I had to find a source of a fake FTDI chip, it'd probably be proprietary programming cables from Chinese direct-import companies on amazon marketplace. So, don't think that just because it's 20 bucks and says FTDI, there's FTDI inside.
Other than that, CHIRP can directly support your device, and really just relies on a serial port. So, you can totally circumvent the ethical issue (of either supporting counterfeiters or supporting a company that bricks other people's devices) by buying a dedicatedly non-FTDI and non-FTDI-compatible USB-to-Serial adapter (there's plenty!), and just use that (needs to have a linux driver. Haven't seen that being a problem.).