wrote
Peter Parry wrote

This requires a power supply to draw no more than 0.5W under
no load (reducing to 0.3W in 2015) and be of certain efficiency.
Linear power supplies cannot meet these requirements.

I guess it depends on the application; if it is something that is
plugged in and switched on all the time whether it is in use or not,
may be this is beneficial, but for something you plug in when you need
and unplug when you do not, does standby current really matter?

No, but most don't use them like that.