I suspect big conspicuous destructions like this are the reverse of US asset confiscation; destroying the thing is a signal that you're really serious about stopping it, rather than just confiscating it and letting the police keep the proceeds.
"... really? You're the guy we seized these from, holding your finger under your nose like a mustache. To cover your mustache."
If you object to the entire principle (or, at least, need to be seen objecting to the entire principle), destroying the assets in a visible public spectacle is the way to go.
California had at least some high profile "street racer" destruction back in the day, and I don't believe any western government, upon seizing a big load of cocaine, goes about trying to figure out how they can unload it to someone else. At least, in easily tracked ways...
Ok, let them buy it again and seize it from them again if they use it unlawfully. Double profit.
> seizing a big load of cocaine, goes about trying to figure out how they can unload it to someone else
Because there is an internationally agreed war on drugs. Cocaine (unlike meth which can be officially prescribed as Desoxyn in the US and heroine which also is used medically in some cases e.g. in the UK) is officially considered pure evil with no legitimate medical use (it can be used for good but in practice 99.9% of its use is abuse and even the 0.1% who use it for good also do that illegally).
AFAIK there is no international agreement on fighting cryptocurrencies mining so far, the mining equipment (let alone the power supply units) are perfectly legal to manufacture, sell, buy, own and use (unless you actually steal electricity to power them) in many countries.
Even such a totalitarian and unreasonably conservative country as Iran officially allowed (and taxed) mining until they found out they are running low on electricity.
This isn't true at all; cocaine is a Schedule II drug, not a Schedule I like marijuana. It has historically had plenty of medical use.
I'm personally glad contractors aren't handling things like this, and would like to see their role diminshed in general.
I have also heard big box retailers (i.e. Best Buy) will destroy unsold items to discourage employees from purposefully hiding or down-selling things in the hope they can grab it for cheap or free.
Though a lot of places will unload these items to wholesalers or discount retailers, and some gets donated to clothing charities. It goes through a few steps first.
Makes me unbearably sad we're such a wasteful species.