Well - how many men did Stalin lose when he just sat at his desk the first few days of the German onslaught in shock and did nothing?
This would be a great rule for me cuz I work fast! Breaking everything up into three minutes sounds overly complicated - why not just one total block of time - "ding" - your done?
Splitting it up is actually much easier.
It is how it is done over at gametableonline for revised and 1942 editions.
Your forced to alot your time per phase, it eliminates the possibly of players using all their time on the first couple of phases then having no time for noncombat moves, this creates very bad games.