you can't compare units like that and call one useless because they have weaknesses. Every unit has a weakness but also strengths. Armoured units are designed to go against infantry and other armoured units. "They are easily destroyed with proper air and support units". Then they can also be easily protected by proper air and support units. Armoured units main resource requirement is components. That gives you plenty of supplies to build support units.
I know armoured units get bashed a lot on this forum by experienced players but you can't think of them as forming the entirety of an army. ASF without other units are useless because Anti air will eat them up. Strike fighters without other units are useless because ASF and SAM will eat them up. Armoured units are just not popular to use because they sink a lot of resources if they die. New players send their infantry with MBT with no other units to invade countries but you don't see experienced players doing that.
I use armoured units for about half my games, a quarter of the games I use artillery, some I use both and some I use neither. There is an endless combination of army builts. Just my 2 cents
I know armoured units get bashed a lot on this forum by experienced players but you can't think of them as forming the entirety of an army. ASF without other units are useless because Anti air will eat them up. Strike fighters without other units are useless because ASF and SAM will eat them up. Armoured units are just not popular to use because they sink a lot of resources if they die. New players send their infantry with MBT with no other units to invade countries but you don't see experienced players doing that.
I use armoured units for about half my games, a quarter of the games I use artillery, some I use both and some I use neither. There is an endless combination of army builts. Just my 2 cents