I never used to be big on perennials with variegated leaves, but my friend David Tomlinson was.
David and wife, Dierdre, have a 3/4 acre garden in Aurora with about 2000 different perennials in it.
David's point was that since many perennials only bloom for two or three weeks, you need variegated leaves to add interest.
Actually, how he sold me on them was his second reason for their use; which is, that they are usually not as vigorous
as the non-variegated forms, which, in turn, contributes to easier maintenance of mixed perennial beds.
I now love a number of variegated forms and also now feel, among other things, that they show off other plants.
Brunnera macrophylla 'Dawson's White':
Phlox paniculata 'Norah Leigh':
For me, the more space, the more 'Norah Leigh'.
This is "my garden" in the sense of a garden I installed and maintained.