I have nothing against it, but like many others I prefer to have everything in one place. I tried an adoptable account and all it did was aggravate me.
Like you said, I understand making separate accounts for things. It tends to be mostly for audiences, as I know I've lost watchers (as well as gained them) as my art has shifted from one category to another - but in that case I believe the artist shouldn't much care. My belief is that art should be enjoyed, not that one draws to please (with the exception being commissions), but draws for themselves.