What's it matter? Most people doing Tiger are high enough level to do it on their own. Hell, i'd RATHER go solo on 24 strikes. That's just me though. But anyways, it's because strikes are tedious and so boring when you do more than like, 2 per session (without friends, it's a bit more fun with friends). Especially if its the exact same one literally 4 times in a row. And if you want to sit back and kill the garbage and trash mobs on the way to the darkness zone, go ahead. I do it on occasion, but i honestly just want to get strikes done ASAP when i grind them. Also, don't i get any Rare/Legendary engram drops that drop from an enemy that i don't pick up in the mail anyways? If so that's a great incentive to leave someone else grinding the trash mobs and getting drops from them. You get what you want, i get what i want. We both win in that situation.