Because cutting the corner cost more time.
Well, that is debatable, but so what, there is a track. You can get a penalty for going 4 wheels off the track down a straight. There is a track, choosing to go off it for no reason is to me, unacceptable.
As for if it's faster, again run off vs clean corner... slower, when you've made a mistake and gone deep, have to turn in tight and go much slower... it's not certain it is slower at all.
But for me, slower or not is irrelevant, it's the simply choosing "I don't feel like doing that corner, it's too difficult, I'm just going to keep going straight".... since when is that okay in racing.
We saw Button do a huge lock up and still made a corner, bottas I think had a large lock up into the final corner and instead of going wide, he just slowed and had a bad corner and lost time as a result. Multiple cars locked up, including Hamilton and lost time in corners. The only other people that went off track were either avoiding collisions (perez and Bottas for example) or had a massive error and had no choice but to miss the corner like Kvyat.
