Only you can decide if any given acessory/technology/product is "worth it". Based on my experience (2 1/2 seasons riding a Di2 Ultegra road bike side by side with a CX bike with manual Ultegra), Di2 will shift more accurately, be more reliable, be easier to shift with gloves, and will generally be more pleasant to ride. For me, it was "worth it" enough that when I upgraded my road bike fro a Defy to a Propel, I had Di2 installed at the shop.

YMMV, but for me it was and is decidedly "worth it".

FWIW, Di2 adjustments are rare (MAYBE once a year, in my experience), but are very easily done, and can even be done while riding, if you know the system. I haven't had any reason to have mine repaired, but I can't think of any reason it would be more difficult to repair than a manual system.