"Worth" is subjective -- it depends on your preferences and your budget. Hence, no one can tell you whether moving to Di2 is "worth it" for you.

For me - and I write this as someone with ample funds and a new-ish Di2 bike -- I would not upgrade an existing bike. While Di2 is nice, and has a few tricks up its sleeve, it doesn't really shift any better than a good, well-maintained mechanical drivetrain.

But let's be honest here: If the OP is asking, he's gonna do the upgrade. He's just looking for enablers.