I owned several Lee-Enfields over the years and I must first admit that I only occasionally used chargers. Subconsciously I may have been conserving them for emergencies or something. Even so, I was always rather amazed that they never failed to work, given the loose nature of the thing and the fact that it was a rimmed cartridge. I believe I did learn somewhere along the way there was a proper way to load the charger but I'm sure I managed perfectly well in ignorance, as often happens. I've never seen an official descrition of the procedure but maybe the came already loaded in chargers, same as 7.62mm ammunition came when we had M14s.
I do, however, take issue with the statement that the Lee-Enfield was never intended to be loaded with a full magazine. For a brief period before charger loading was introduced, an extra magazine was indeed carried in a specially shaped buff pouch all of its own, again no doubt intended for emergency use only. That was in the Slade-Wallace equipment. They must have had second thoughts about it and the concept was discontinued, although when charger loading was introduced, the magazine cutoff remained. Jeff Cooper suggested his Scout Rifle have a magazine cutoff, so it must be a Good Thing.
I also owned a Mosin-Nagant carbine, which also used chargers for a rimmed cartridge. Again, it was amazing they worked so well, not to say easily, but the Russian rifles had a little gadget to assist in preventing double feeding. I'm not sure what it was called, maybe an interrupter or something, but it allowed easy loading of four rounds and closing the bolt on an empty chamber. The trick with the Mosin-Nagant chargers was that you had to have a good charger. I had some that were not shaped correctly and they would not strip from the charger at all. I attributed that to aftermarket chargers, a problem that seems to occur a lot with magazines of all sorts. But I never had that problem with any Lee-Enfield chargers.
I've also owned other clip fed rifles, including various Mausers, MAS-36 bolt actions and a Remington Model 8, which actually came with stripper clips. I never successfully loaded it (in .35 Remington) using the stripper clips. All of the others worked just fine, though to say "easily" would be a slight exaggeration. However, the differences between cartridges of the different calibers, from 8mm Mauser, 6.5x55 and 7.5 French, was enough so that there was no interchangeablity of the stripper clips and they weren't all marked as to cartridge, either, though some were. Good idea, just the same, the stripper clip. I think they are just as valuable for what I call "ammunition management" as they are for fast reloading.