As far as I understand the W3C standard, something that starts with did: is supposed to point to a document that describes a subject. That’s not the case here. The account label identifies the account directly, not indirectly through another document.
But something like hierarchical like ic:rc1:nmkbs-aaaaa-aaaam-aadfa-cai.0 would indeed be nice. Easier to remember because everything on the IC will start with ic:.