No, CHERI supports sub-object capabilities.
This "name overflows to is_admin" example doesn't come up in real code or real CVEs. It does come up in HN comments on Fil-C threads though.
CHERI is less compatible than Fil-C, in terms of how many changes you have to make to code to make it work, and this is an example of a policy decision that causes that result.
It is interesting that C++ decided to disallow it in compile time evaluation ( constexpr contexts ).
I have already seen fixes where code that used pointer arithmetic to go from one struct member to another generated garbage in real-world gamedev projects. That code had been like that for 20+ years and worked fine, then suddenly broke after toolchain update.
You can also limit access permissions IIUC; I'm only going by old memory here, but you'd be able to hand out a read-only pointer derived from an RWX pointer.