Perhaps you mean a few video cameras can use the USB-C port for storage. I am not aware of any stills / hybrid cameras that can use their USB-C port for storage.Quite a few cameras do have USB-C port for storage. I use this with a Samsung T5 on my Black Magic Cinema Camera. The trouble is that we already have different standards for SSDs that aren't great for cameras (M2 is quite large compared to some camera media).
It will probably settle on CFExpress - but even then there are two common sizes (A & B - there's also a C, but I've never seen it).
There is still a big price differential at the lower end compared to SD cards - up to 5-6x at the bottom end for the same capacity (although it tips in CFExpress' favour at the higher end). The fact is that most casual and pro-sumer users simply don't need anything better than a V60 /U10 SD card (60MB/s write sustained) for 4K video and considerably less to take photos. An 800-1700MB/s CFExpress card is overkill. Sure, it's fast to transfer your photos & videos, but not really "necessary", unless you are a pro who has to offload hundreds of GB per day.
CFe has standardised on Type B. Only a couple of Sony high end cameras use Type A and the capacity is small and expensive and currently only Sony make them - although there has been some announcements for delivery next year.
Most of the users that you are referring to are using cameras that already have USH-II SD card(s) ie no CFe cards because the camera is not capable of 4k/120 or 8k raw. Those cameras can are capable do need a CFe card to record internally. Atomos Ninja V+ can record 8K from the Canon R5 but that is the only option unless you include codecs that already have compression eg Sony A1.
Type C has never been commercially made. They are large and I don't see the point personally.
The price comparison between USH-II SD cards and CFe Type B cards are similar although the CFexpress cards are easier to find. CFe cards come in much higher capacity options if you are prepared to pay the price!