Anyone who can't load faster AND more comfortably with one...is using it wrong.
You can hand it to someone with less than optimum hand strength (young, old, arthritic) and they can load mags, period, which is reason enough to get one.
For handguns, it's faster than hand, faster than the factory sheetmetal or plastic loaders that come with some, faster than other aftermarket loaders. Hardly any more effort getting the last round in than the first, if you have extra-power mag springs or +2 extensions or notoriously-difficult-to-top-off mags.
The rifle-specific models: for some, strippers are quicker - IF you remembered to bring your spoon
. They do unload
FAL, AK and AR mags quickly - don't know about other models.