Surely better than yet another nail bar or chicken shop? I doubt it would get the footfall a Pret needs though - yes there will be more people working from home now but you can make a Pret sandwich yourself in your own kitchen. If you’re going out for lunch you want cooked food that Pret doesn’t supply. They would have a lot of competition in the coffee market too, so not sure that’s a runner.
I really can't see Pret opening a branch in Sydenham - or even in Penge, for that matter.
Indeed, on my relatively rare trips to London in recent months, I've been aware that one of the very few positive things to have come out of the pandemic is a culling of the excessive number of Pret branches in various areas: in some places it used to be that you couldn't go 100 yards without encountering one, which really was a bit ridiculous.