Is ANR worth it in the DHC-8?
 

Yes, it makes a difference, especially if the NVS is deferred (Q-200). I use the Bose QC2 with the UflyMike. It's less than half the cost of the Bose and twice as better IMO.

Doesn't the headset die if it runs out of batteries? If this is the case what happens when you realize "whoops, I guess I dont have any batteries in my bag."

you turn on the overhead speaker, and buy a AAA in the terminal

In that case suck it up then use the headset that should be provided to you by the company... I know Piedmont provides Telex headsets for the dhc 100 & 300.

There's a kit you can get to convert a set of DC's to ANR.

a few years in the dash, ANR not necessary, maybe 5% of guys on our fleet used them.

If you are flying in west where you might get up into the twenties you can even go off headsets and use the speakers in cruise...

ANR is worth it in any airplane you fly...it certainly has been for me from a C172, a Cirrus SR22, a King Air, Beechjet, CRJ or straight-wing Citation way up at FL450 where wind noise is almost nil.

Helping save your hearing is worth every penny IMO.

Outside the box idea....

I flew the shorts, very loud. I bought the Halo from Quiet Technologies, then got custom ear molds (for shooting ranges) drilled a hole them, and put the speaker tube into it. I did this because it was more comfortable than using foam ear plugs, especially for long flights. But then I wondered after a few years if Bose was better, so i bought the Bose X. Brought both on the flight, tried them one after another, side by side, did this for a few flights, and the Halo with the plugs was just as quiet, no differences in the sound cancellation. 1/4 the cost, and way more comfortable. This is in agreement with reviews I've read about he halo vs. the bose on different forum threads. So I sold the bose. Also wore the telex 850 in the citation, couldn't stand how loud it was at lower altitudes, brought in my halo the next day. You could also do this with any in-ear headset.