Bedrock does not currently support being "uninstalled"; it has to be formatted over, like traditional distros. This is for two reasons: (1) I currently have no way of ensuring any one slice of the system is functionally complete such that removing the rest of the system would leave something bootable. (2) I don't want to advertise support for something active Bedrock users do not themselves regularly exercise, and by its very definition active Bedrock users won't uninstall Bedrock. In theory with enough effort Bedrock could be made uninstal-able, but I don't plan on investing effort there. If a user is interested in testing Bedrock out, I recommend using a VM or spare machine.
In every other workflow I can think of, Bedrock can functionally mimic being an alternative packaging system on top of whatever it supports. You can get most of your system - including the install process - from some distro, then use Bedrock to get features from other distros in a way that "feels" like it is "on top" of your original distro. Whether it is "on top" is a matter of semantics rather than practice.
With the next major release (0.8) I plan on supporting running Bedrock in something akin to a container. This would let users uninstall it and be less ambiguously "on top" of a traditional distro, but come at the expense of not integrating with the host environment.
[0] https://en.wikipedia.org/wiki/Ship_of_Theseus [1] https://plato.stanford.edu/entries/essential-accidental/
