It was a complete and total abuse when people would just scuttle the units that RA gave them for money, basically allowing you to use phase stabilizers as extra trade ports. RA can still be used to raise a pretty substantial army at a low cost very quickly, but it's a much later game feature.
It's certainly not in the "useless" bin of upgrades. There still remain several upgrades which are absolutely or borderline useless because they cost so much to bring out and have so little effect that there's never a practical reason to invest in them. RA is not something you rush for anymore, but it's still good!
