I use group keys but I tend to use them for unit division:
Group 1: Raiders and frontline units
Group 2: Escorts, riots, and assault units
Group 3: Constructors
Group 4: Skirmishers and artilleries
Group 5: Artilleries and heavy artilleries
Group 6: Demi striders, striders, miscellaneous, captured, and resurrected units
Group 7: Special units
Group 8: Anti-air units
Group 9: Static artilleries and superweapons
Group 0: Scouts and disposable units
Should I practice not doing this?
Because I figure out that group keys could be used as quick selection for units on each side.
Like Alpha, Bravo, Charlie, Delta, Echo, Foxtrot, Golf, Hotel, India, Juliet