CF cards are actually really good and reliable. It’s used a lot in the professional equipment like DSLR’s, etc.
CF has now been superceeded by XQD cards and CF express cards.
They have superior transfer rates as well compared to SD.
They are more expensive than SD cards, but professionals care about reliability and resilience.
That’s why you see them in many modern photo cameras and production equipment.
So I see it as a plus that Elektron is opting to use CF instead of SD.
Since it provides piece of mind for professional musicians who use these devices for live performances.