How does it work?

I'm not the dev, but from his description it sounds like you tell the module to start listening for changes on your development site after you've made a dump of your live site. When you've finished making your changes the module prepares a bunch of sql queries which when run on your live database will update only the changed aspects (i.e. newly developed functionality or additional features etc). This would allow you to add or change functionality to a live site without overwriting anything done on the live site since you made the development database dump. This is always a problem with Drupal and this module would seem like a way of dealing with it.

To me it sounds like an excellent idea.

In brief, this module does two things:

1) Take the snapshot of data and schema of database. It is sort of reading the database and saving it in a file on localfilesystem.

2) It can compare different snapshots to find the differences - ie, find what all data and fields are not common between the two and show it as SQL query.

So On day 1 of your project development, you can take snapshot of your local database with say snapshot_day_1. On day 2, you can create new snapshot snapshot_day_2 and run compare tool to compare difference between two snapshots snapshot_day_1 and snapshot_day_2.

Thus you can see what db changes were there when you make any modification on the website...either creating a node, or updating any setting.

It is very helpful to learn what tables are updated on a particular action.

It is helpful to find the changes made when some setting is changed and deploy it to database instead of deploying complete database.