IBM compatibility was the holy grail in 1985. No business was using anything other that a PC at that point. If you wanted to get into a business environment you had to be MSDOS compatible which is why the crowd cheered!
Bob
I get the concept of IBM compatibility, was just looking at it from a compartmentalized/Amiga-centric point of view. Had real Amiga users (that wouldn't have been there anyway, since the machine was so new) been there, the atmosphere would have been a little different. I can almost hear them scoffing or booing at the announcement. lol Even the speaker laughed as he cracked a joke about MSDOS compatibility. Taking as long to load as the real deal.
But yes, from a strict computer sensibility stance, Commodore obviously knew and had the gee-whiz to demonstrate that feature of the machine for the cheers they banked they'd get.