That can work if you are lucky and your SmartThings hub is running on a zigbee home automation channel which is also a ZLL channel. It just won’t work for everyone, which is why there’s a caveat.
(And of course you did have to use the second device which is the Hue dimmer.
The Hue dimmer can factory reset a Hue bulb which is on a ZLL channel like 15 or 25.)
People run into a problem when their SmartThings hub is on a ZHA channel like 14 which is not also a ZLL channel. The Smartthings hub will change the bulb to its own frequency when the bulb is directly joined to it. Unless that frequency is one of the ZLL frequencies, a ZLL device like the hue dimmer won’t be able to talk to it anymore. So they won’t be able to get it to reset.
So it’s just a matter of chance as to what frequency your own SmartThings hub is on. The method you describe is the standard method for devices on a ZLL frequency, So if you’re lucky and that’s one of the ones your own hub is using, the standard method will work.
If by chance your hub is using a different ZHA Frequency, one of the ones that is not used by ZLL devices, Then the standard method won’t work. Which is why you see so much discussion in the forums.
In the US, the Lutron connected bulb remote (not the similar looking Pico) is able to reset a bulb on any ZHA frequency, which is why that has become the method of choice in the US.
If you are in the UK and you are Lucky and your smartthings hub is operating on one of the frequencies that ZLL uses, then you can use the hue dimmer as you did.
If you are in the UK and your smartthings hub is operating on one of the non ZLL frequencies, Then you have to either use the Dresden device described in this thread or find one of the old non-Hue color control wheels to do the resetting.