- Use them as an additional map layer for tiles in the editor!
My test version is a bit advanced, but someone smarter than me should be able to make a script everyone could easily use.
- Set an automatic battleback for those areas/fights.
- Change the encounter rate.
- Tell a script to create & put a premade event there, like those "Quick Event" buttons. They could be automatic, or you can edit them in the editor after hitting playtest, then re-opening the project.
- Anything you'd have used Terrain Tags for in the past, and they're here in VX Ace too.
- The new "noteboxes" for both tilesets & maps makes these incredibly great -- and you can change tilesets at any time on the map with an event command. For example, someone could use them in a "dynamic lighting" type script where your noteboxes control how powerful/color they are, and you paint maps with a few regions where different types of lights appear. (Scripters, this is a hidden field you can access using .note - ie: $game_map.map.note & $data_tilesets[id].note)
And if you don't know or like scripts... you can also use events! One of the new commands on the last page will get the "region" of an x,y location on the map. Couple that with an autorun or parallel process for all kinds of awesomeness. For example, those push thingy puzzles. Check the locations they're at, and if they're both standing on region #5, it's won.