Does it serve any real purpose on the desktop though? We have justification of these slow, cooler, low power cores in the laptop market, and certainly the handheld market, which should all be C-cores if you ask me.
But other than marketing, what would adding 4 or 8 more slow C-cores actually offer the desktop user?
Intel is f'd without them due to not being able to power or cool much more than 8 P-cores, but is AMD in that boat?
Any sale lost to a competitor is a loss.
My thinking is simply that with proper thread management, the c cores could carry most of the dumb stuff in the same way Intel use the e cores. AMD sacrifice some power draw having both the IO die and core chiplets. Additionally the IO interconnects to the core dies also are a tradeoff - in a performance per watt scenario if Intel were not a process behind then they may be able to consistenly pull better idle/low load power usage.
Unfortunately the reality is that for the majority of the time most people
are using their computers have their computer on, a large part of that time is spent with at least one core idling.
Again my main point is to have low end AM5 products - the AM4 train will end at some point - currently AMD doesn't have much flexibility in the proper desktop lineup for low cost solutions (it's either full cores and IO or a laptop/pheonix derived hamstrung part which doesn't reduce cost enough). In reality AMD are probably racking up a few zen4/5 chiplets where less than 6 or 8 cores are functioning - they may be trashing them but I suspect not however there is no SKU that's using them. The problem is a quad-core AM5 CPU with an IO die and chiplet will be more expensive to make and use more power than an i3. Now if it they were combined with a quad c core then AMD could push the power / TDP leverage "because 8 cores" and recoup some money from that crap silicon selling at a percentage lower than the normal Ryzen 7 but offering maybe 75% of the performance.
The other fringe reason I could see such chips (c cores on IO die only with no added chiplet cores) being popular is if they were real cheap, they would be real handy for diagnostic / BIOS flashing purposes...