Different people want different options. Choice is good.
The Logitech button is a cloud to cloud integration, which does introduce a small amount of lag.
And sometimes it’s just a matter of aesthetics. The pop button is rubbery and neon colored. Sometimes people are looking for something that, well, looks more like a light switch.
There are several other battery powered devices which are available in the UK, some of which are Z wave and so communicate directly to SmartThings.
For example, the Devolo scene controller is very popular. It also costs less than the pop button once you factor in the price of the required pop bridge. It has several style and color options.
And the remotetec has eight separate buttons, each of which can be used for three functions (click, double-click, and long press, just like the Logitech POP) so that gives you 24 functions on one battery operated device.
All of the battery powered devices that work with SmartThings are listed in the buttons and remotes FAQ linked to above. Including the DeVolo, the Remotec, and the pop. Here’s the link again:
So the pop is definitely a good device (I have three of them), and there are several other good ones as well, each with somewhat different features or aesthetics.