I think the title should be the mentality of the net list.
I may have played a net list, though not conciously so.
It is an interesting construct that we have a hobby with great options but we discover a very good army build up and that becomes spammed. I would agree that there are some options that work better than others at doing specific things, for example I think that the missile laucnher is the best option for tactical marines with their ability to frag or krak. I also bemoan those choices which are in the codex which you can't really see the use for and so never include them, like I have never found a use for shotgun scouts.
But the problem arises with net lists where they do not meet your local playing conditions. I have had problems beating my brother-in-laws nids and so posted the list I was using for some advice, one of the suggests saw putting melta bombs on every sargeant, magna grapple and replacing all special weapons with meltas. This was back in 5th where you couldn't use grenades against things other than vehicles. So a lot of the options were redundant, another replaced high (relatively) rate of fire weapons with single shot high strength again it was aimed at popping armour, something that is lacking in a nid list.
But ho-hum, there are some advantages, as has previously been mentioned, they tend to have a large turn over of models so spend quite a bit with GW, which can only be a good thing, the other advantage (possibly) is that you have a good idea of what you are going to be facing and so can counter those options with how you design your list.