[Pharo-project] Metacello Why symbolicversion and not simply tagged version:?

[Stéphane Ducasse]

Dale 

in my goal to reduce the complexity of metacello, I'm wondering why 
symbolic versions could not be expressed as version:

because 

        version: #stable 
        version: #development 

are symbolic versions and there is no clash possible with 

        version: '1.1'

Stef