All the stuff like sending emails, sending DOGE, etc. would be done on the forging node's services modules.
How on earth would you guarantee that "stuff like sending emails, sending DOGE, etc." were indeed done by forging node's services modules?
I have absolutely no reason to believe this would be safer than just using a third party gateway -- at least there I could complain to someone if "stuff wasn't done"
This is total fail.
I would never trust it
So you would trust centralized exchange where you have no visibility and single point of failure over open source published code (services) running on 100+ servers? XCP implemented a BTC burning mechanism that was totally automated. It monitored blockchain and automatically credited XCP to bitcoin addresses that burned to a specific address. Over 2000 BTC and when problems happened the XCP devs answered support requests via forum.
Yes, absolutely I would trust a trusted gateway (with good reputation) over an anonymous Nxt node performing things like "sending DOGE and sending Bitcoin" using it's services modules. There is no reason to believe the node's "services modules" performed these things.
With a trusted gateway I can complain and maybe they can resolve the problem (they need a good reputation to stay in the business) -- an option not available with trusting a Nxt node's "service module"
This is really stupid idea.