Changing over to VFD and 3 Phase Motor

Finally made up my mind to change over to 3 Phase with a VFD for my
Mill-Drill Machine.
I got a good deal on a GS2-22PO Drive from Automation Direct.
I should be able to controll the Spindle Speed from the CNC-Controller
with this Drive.
Now I need to replace the single Phase Motor with a 3 Phase 220 volt
Motor.
A lot of advertisement about Vector Duty Motors and Inverter Duty.
These Motors are considerably more expensive.
Are they really worth the extra Cost?
I assume that those features will give a wider usable range of Spindle
Speeds without changing Belts.
Is it worth the difference or just a bunch of marketing?