Yes indeed as a fourth ability, allow you to repair your mech more easily than with scvs.
Problem with repair scv is that most of the time, it is very unreliable.
Unless you go pure mech I rarely see scvs being added to the mix to repair the mech units.
Here’s the problem with scv repair
- You need 4-5 of them which lower your econ
- Fragile and exposed, have to survive the fight to repair
- Need the target to be immobile to repair it
- Need to be in range of that unit (flying unit over a dead space)
All of this makes SCV repair quite unreliable except in heavy mech composition with thors where thor act as meat shield while scv repair it from behind.