Pretty sure that DR says that the only reason he puts one in his PSK is because people expect one in there..
"The decision to include the fishing gear was not easy. One could easily argue that it is relatively unimportant in the grand scheme of things for a kit designed primarily to help support someone for a brief survival experience where sustenance, food, isn’t much of an issue." from the FAQ on the PSK page.
Actually, I personally think that DR is wrong about this one. The Survival kit is supposed to provide signal/fire/water purification for 1-3 days. But it could be streched to a week. Under those circumstances a decent fishing kit becomes desirable.
I have tweeked mine by adding:
6 more hooks + split shot.
1 silicon jig.
40" Spyderwire.
40" Braided fly-fishing backing line.
I have also added 6 more Tinder-Quick and 10 lifeboat matches with striker. Just in case I loose or break the Spark-Lite.
I personally am of the view that you should go into long term survival mode on day 2 of a situation and start hunting, trapping and fishing in earnest.
I would also urge anyone who has the good judgement to carry the RS kit to add a water bottle, knife, metal cup, 40' of cord, lighter, torch and something to waterproof a shelter with. Bin bag, mylar blanket, AMK heat sheet, poncho etc.