OK I understand that but my experience is on several older rental properties which had been rewired but retained the original imperial boxes [with 4 fixing lugs, 2 each on top&bottom] and the metal clips simply pulled off. Initially I assumed they were adapted car type clips until I found a packet under floorboards.I bought some for my kitchen sockets and for the money it cost (think it was about £8 when I bought them) it was worth it just for the lack of hassle. My sparky thought it was a waste of money and I should have just changed the back box or jammed a self tapping screw in but for me it was money well spent. I can see why a sparky might not rate them but I always want my sockets etc easy to take a part and would even have paid twice as much for a repair that is so simple to do and easy to dismantle afterwards. I've since had the house rewired during the rebuild, otherwise I would post a pic. There are other brands too that work slightly differently and might be better depending how much of the screw lug is damaged or missing.
I changed a couple of BB's on first property but second property didn't want the new decor damaged so drilled and tapped rear of BB to use long screws.
On 3rd or 4th visit I went round and checked the lot.