I don't like it. Having a physical object the embodies your phone's identity is a lot easier to deal with in many ways than an ethereal emulation of said object. For instance, if I'm traveling I can just buy a SIM card at a kiosk and pop it in, even if I can only communicate through little more than pointing and grunting. Another example: I got a new phone recently, but since all my stuff was still on my old phone, a…
Personally, I would also prefer to have the SIM-tray as a backup and for travel. Most prepaid plans in Europe still don't support eSIMs.