fwiw, I find this feature valuable, because I create Perspectives for usecases that are specific to the form of the device (desktop, phone, and so on).
For example, on iOS, I limit favourited Perspectives to only what can be displayed without swiping to reveal.
On a tangential note, I’d personally find it useful for time allocation to have optional task number badges on Custom Perspectives, like badges on Inbox and Flagged. This feature would be more useful on mobile to me, rather than desktop, but both would be nice. (related, related)
