ECDIS is not a requirement. You can be (as you have been) licensed without ECDIS. However without it they will put that limitation on your license. If you did take it before or if you take it in the future you can have the limitation removed.
I can only guess NMC must have mistakenly omitted this requirement from my reinstatement requirements letter.
Assume this is an endorsement which can be obtained through an approved course? Anyone have any recommendations? I’ve noticed that even among USCG approved courses there is some variability in running hours. wonder if there are any cost/time efficient approved courses out there
ECDIS is for STCW only. Licenses (national endorsement) are not limited to vessels without ECDIS. On STCW, if your stuff was expired and not in continuity,. your last renewal was probably before 2015. ECDIS did not become required for STCW for vessels until January 1, 2017. So I assume you have never taken an ECDIS course - that’s the only way to not have your STCW limited to vessels without ECDIS. The courses all have to be of a minimum length, so you are unlikely to find significant differences in time and thus probably cost. They all have to be done live (or almost all live) as the courses needs the use of ECDIS equipment.