Our lot do the same. As I remember for 732, a few lights for fuel pumps, elec, and pitot static illuminate but that's about it. Rest taken care of by the transfer bus. All sorted after 1 minute once the APU has come alive.
10,000 ft then APU off:- Could argue about it for ages (ie. do you restart it over high terrain etc, do you accept an aircraft with an inop APU...) What I am sure of is this...my lot wouldn't pay the fuel bill to run it across all our fleets for the extra 30mins of running per sector.