I have a perfectly nice CF bike with CF wheels and SRAM Force. It does everything I need to do. I have experienced some of the downsides of CF RIM brakes and wanted to to move to disc. My first time using disc was a rental coming down Haleakala in the rain and I was converted. I recently decided to start looking and came across something with disc and eTap that I piqued my interest enough to part with money. I had no logical reason to spend the money as there was absolutely nothing wrong with the previous ride.
That said, even though it was the most expensive bike that I'd ever purchased by 2x, I have zero regrets. I love riding it and have been riding more recently than in the past 4 years (even discounting our new Covid reality). The disc brakes are fantastic and I've really grown to like eTap. The former are definitely with the money to upgrade for, imho, the latter are nice but I'm not sure I'd pay extra.