Colon is illegal character for filenames in Windows. Allowing colon in filenames on Linux would go against Obsidian’s aims/benefits “unparalleled interoperability” and no “lock-in” claimed on Obsidian main page.
Colon is just one of many characters desired in titles. Ability to decouple title from filename would solve all of them and would allow use of permanent identifiers while still allowing to rename titles. Necessary functionality is requested in:
and