What is momentary type footswitch? And what about latch-type?
When we talk about a latch-type footswitch, we're referring to a kind of footswitch that remains on status once triggered on until you operate on it again. For example, a light on/off switch. Latch-type footswitch does not require continuous compression from players, which is great for switching effect pedals on/off or switching between amp channels.
Momentary footswitch is different: it remains on only as long as it is being compressed (e.g. a lighter with a press button). When you do a single press on a momentary footswitch, it will generate a short on-off "pulse", which is recognized as a "trigger" on most digital multi-effects for switching presets, tap tempo, toggling effects on/off, etc. So momentary footswitch is mainly for controlling a digital gear.
What else can I use Ampero Switch with?
As aforementioned, the Ampero Switch is designed for not only Ampero, but also for other devices with momentary footswitch controller support. The function you can have will vary according to the device you're going to control.