[ssupermegatone]

Kimi had "fresher" rubber hence better acceleration.
Shoe had old rubber hence did not want even battle it out risking both of their races.
With less grip and at those speeds shoe just made the right call not to risk it out of the optimum raceline thru eau rouge or even before it.
Was he even thinking to let Kimi pass before the drs-line to jump him again end of the strait?
Either way Kimi read the situation far better than anyone here in this forum and did that in a split second.

Id say good move.