I have yet to see anything I could use Dynamo for on the MEP side of things (other than maybe extracting info to Excel).
I'm in MEP side and I can see lots of benefits, anything repetitive can be done with Dynamo.
We are currently looking at
Creating views with added templates
Creating Spaces from Rooms
Also I've used it to copy parameters from a linked architects model to an excel sheet, then copied that sheet back into our model, but populating our shared parameter information.
What I'm aiming for is a set of Dynamo scripts which can set up a project for us, quickly. all our standards in place by running a few scripts sounds good to me.