The harshness is VERY subjective. You will also find that the majority of owners (of any car) are just very happy and don't bother posting about harshness etc. You will have to go and drive a ZCP car as well as a regular car in order to make a call. If you can 'stomach' the ZCP ride then go for it. I still don't think the Comps are anything close to an actual 'sportscar' harshness or feel that you would find in a special 911 or Cayman - certainly not to the degree it should be a make/break decision.
I retrofitted all the competition suspension stuff to my F10 M5 and found it to be worth the effort since the stock car was way too 'comfortable'/soft. At the same time guys were wanting to swap Pirellis and Michelins out for tyres that would give them more compliant ride (why not buy a 7 series, I don't know... but anyway) and still others were fitting KW suspensions at great cost because they really should have bought an M3/4 instead.
Think about what you're gonna do yourself as well: if you are going to lower the car anyway or fit a different exahust anyway or tune it anyway etc then the list of reasons to buy a comp becomes shorter and shorter... I didn't get an F90 comp but also partially because the comp wasn't going to be low enough anyway and I fitted the M Performance HAS system. I had plans for Dinan suspension stuff at some point in the future if the time comes (but the F90 was a much better feeling car than the F10 straight off the bat even in non comp form). With the Corsa tyres it seems to have met my preferences for now.
With the F8x, the cars I've driven don't feel very hard to live with in Comp form... granted I have never had to live with them. This is a very personal thing to decide on because we are at different ages, states of fitness, weights, heights etc. Is it nice to have a comp? Of course it is - for me even just for the seats

, However everything else can be retrofitted or improved (for a price) and you can get way more power even from a very very conservative tune.
Our definition of less than perfect roads is also very subjective. If the road is too bad for a comp, chances are it's going to be very nearly as bad in a regular car. You won't suddenly feel like you're in a Rolls Ghost if you choose the non-comp. I have found people complaining about Midrand roads which have the odd pothole I drive on these all the time just fine... then you drive through Fourways and some of the main roads are basically disintegrating... and there are tons of M/comp/Porsche drivers that drive around there every day... you can treat it as a slalom course

then you get roads that need an actual SUV to traverse in other provinces (Stares at KZN). You work around having lower or sportier cars from a height perspective as well as the type of tyres you have on them. It isn't that big of a deal in reality.
From a utility/daily use perspective it is also subjective. The point where I'd guess it becomes difficult for me to live with a car is something like a GTS or DTM M4 - or RS Porsches. For other people this threshold is a base M car let alone a Comp. I regularly do grocery and school runs in my 4C which some would find undrivable for daily use (and every second 4C youtube video is about practicality or daily driveability on what is meant to be someones 3rd or 4th car

).
Go have fun driving and experimenting. If there is something that is a must-have for me it would be the EDC/Adaptive suspension.