Yup, no reason not to do that.
Potentially, users could make several alts for different topics. Although that may be more trouble than it’s worth.
Another option would be to curate content at the level of the individual note. That would have its pros and cons. Ultimately, content could be curated using both methods simultaneously: curation of pubkeys and curation of notes.
I’m thinking initial rollout would curate pubkeys though, not notes. Easier for clients to incorporate that way. Just swap out the list of pubkeys in the filter they’re already using for the content fees.