I don't believe what OP has said is true. There are multiple reasons for rushing through the level. Some people bank on the end roll, but for me I usually rush through to complete a bounty. Because in my opinion, completing as many bounties as possible (most of which have something to do with strikes) is the best way to get legendary gear. In my entire time of playing Destiny, I found only one legendary engram drop, and that was driving back and forth between loading screens to farm as many enemy kills as possible. However, by completing bounties and earning vanguard or faction marks, you can gain access to Legendary gear a lot quicker than farming or banking on the end roll of a strike. Also it gets boring having to kill the same enemies again and again.