I've never observed a difference in flavor between a beer I left in primary for 3 weeks, bottled vs one I've left in primary 3 weeks, crashed, added bottling yeast (neutral champagne yeast), bottled. Maybe you gain a little on how quickly it carbonates but that's a huge maybe.
I think what you're getting at is could we leave the beer in primary for 1.5-2 weeks, crash, add bottling yeast, bottle and get the same product? Never tried it. If that idea holds, it's still going to take some time in the bottle at ~RT to clean up so it's six of one and half a dozen of the other.