My point of T4 in Diplomacy/Marauding is access to Leonis/Sirius sectors when you are usually not allowed to enter, that gives access to the Clusters there and that means Defari Doctor(s) for the KDF and at least 4 Blue DOFFs for Feds.

Now you can whine about not being able to use the power on yourself but if you do Cryptic will either do 2 things.

REMOVE the Coil bonus since the duration is more that enough for anyone to get there or allow you to use it on yourself ... and nerf the crap out of it, like a 10 minute duration with a 20 hours cooldown.