He mentions that Vx is close to stall speed - ever heard of Take Off Safety Speed? The manufacturer states this is the minimum speed until 50' to ensure controllability of the aircraft in the event of an EFATO.
Someone will correct me if I'm wrong (DJPil?), but I'm pretty sure that take-off safety speed is a uniquely Australian manifestation probably going back to the old DCA. It used to be in the old uniquely Australian performance charts, but I' can't recall ever seeing it on a manufacturers chart.
The bit about "The manufacturer states..." is wrong. The take-off safety speed is defined as 1.2 x stall speed. Co-incidently, 1.2 x stall speed is used in FAR 23 as a performance hurdle, but its not intended to be a target speed used by the pilot, its more of a certification protocol.
See here:
eCFR ? Code of Federal Regulations
I'm with John Deakins that for relatively high performance aircraft like the Bonanza that vx & vy have very little practical relevance, I'd disagree with low powered aircraft.
Take off in a C150 (yes C150, not C152) from Bang Pra airport on a hot day in Thailand with high tension wires in front of you and I can guarantee the only speed you want to know is Vy.
But, take-off in pretty much anything retractable and its Carson speeds that you want to understand.