My idea is that if for whatever reason you disarmed an squad that you didn’t use to get some credits to use, and later one you change your mind. Wouldn’t it be a good idea if there was an option to buy it again on the tech tree?
As you already unlocked it, it wouldn’t be too crazy to acquire it again, as for instance, some vehicle squads (tanks, fighters, and bombers) do have some exclusive vehicles for each one, and if you did sell those, you are basically softlocked into using these without any real alternatives