Will elementary OS make lots of snap packages?
Does the snap package mean stable OS + new softwares?
https://developer.ubuntu.com/en/snappy/build-apps/
Please do refer to this link to have a better idea. I believe it's the new way, similar to windows where one can easily install applications. However the old ways are also going to stick around.
Snaps means, that you can install Software, without installing dependencies, because all needed dependent software is already part of the snap-package. All installed software coming from a snap is located in the filesystem under /snap unlike .deb packages, where it will be install allover the system. Means you can also install different versions of the same software. For example /snap/firefox-49.0.2 /snap/firefox-49.03 /snap/firefox-50.0.1 So the installed software is only in that one specific folder and no where else in the filesystem.