Engr27 expressed it perfectly: But it is the easiest to value.

Not always, but mostly. I still have puts with strikes $390-410 I bought in the first half of last year when from around $400 Berkshire did shoot up to $440-450, convinced it won't remain at that relatively(!) high valuation forever. As it did not but went even higher and higher those puts are near worthless currently.

But I made far more money than I lost by then being more conservative and buying puts again only when it really got extreme (in my view) => over $470. And then not long running puts with strikes 10% lower, thinking within a year Berkshire might come back a lot. Instead puts just $10-15 lower than current price. A different strategy, betting on a quick counter reaction of a few % down after a spike upwards from an already for Berkshire "extreme" level. With expiration 2-4 months out as it's a short term strategy but I can't bring myself to buy puts expiring in 1-2 weeks, that would be too much for my nerves. I need a little "margin of safety" = time.

That short-term strategy up to now worked every single time in the second half of last year and this year. I bought when the price did quickly rise to $470-480, and sold a few days or weeks later --- with me having bought just the day before Jim's warning puts again (strike $465 and $470, expiration May and June).

The context to "easiest to value": This $470-480 level seems to be for many investors too far above Berkshire's usual Price/PeakBV valuation "channel" I posted not long ago, too extreme, therefore if there is a spike upwards at that already high level, then many can't resist the temptation to use this excellent opportunity to quickly sell Berkshire shares (that's at least my interpretation of why then always this "fallback" happens).