The emphasis was on the word technical. The only technical argument I've ever heard against using tabs for indentation only, was that some software text editor a long time ago mangled tabs. In my anecdotal experience with computers plus working with some embedded telco hardware dating back to 2000 and some even earlier, some with rather old or non mainstream OS, I've never ever seen a text editor which mangled tabs. Nor I've never met anyone who seen that happen. Maybe it happened in the mainframe age, but I suspect even that software has been upgraded over time.
Sure, PEP8 an other standards prescribe spaces, and I of course always use industry standards myself too. I'm just saying that there is no technical merit for that demand. The water pipe in the monkey cage has long been shut down. The only reason to demand spaces for indent now is circular - that other standard is demanding them, therefore we need to do the same, and that other standard uses the same circular logic himself.
