What points reward
A cumulative championship measures a season honestly: the driver who was best most often wins. Its weakness is that a dominant campaign can settle the title with races to spare, leaving a stretch of competition with nothing at stake. That is a real cost, not a purist's imagined one.
What elimination rewards
Cutting the field guarantees a live finale, which is genuinely better television and genuinely worse measurement. A driver who was marginally the best over months can lose to one bad afternoon. Anyone claiming this format is fairer is arguing something other than fairness.
My preference, stated plainly
I prefer formats that lean towards measurement, because the season is the sport and the finale is a bonus. But I do not pretend the alternative has no case. The dishonest position is claiming a format is both maximally fair and maximally dramatic, which no format has ever been.