Gremlin is a stealthy tank that, when cloaked becomes impossible to spot for your enemy. Equipped with light plasma weapon and having weak armor it doesn’t stand a chance facing other T2 units. Don’t use it for fighting.
Use packs of 4-6 Gremlins to sneak in beyond enemy defense lines, get intel on plans and sabotage the economy.
If you see an unguarded base try to first disable its buildpower (destroying construction towers) making your opponent unable to react. Then go for Energy Converters to get a nice big chain explosion and finally strike Fusion Reactors and other eco. It can be detected if it comes into vicinity with enemy units or if your opponent has an Intrusion-countermeasure system.