What is the utility? Sure it makes money laundering and buying illegal goods slightly easier than dealing in cash but otherwise what's the point?

In part, one of the points is to disallow a country from forcing bank depositor bail-ins. Like 2013 in Cyprus. https://www.theatlantic.com/business/archive/2013/03/everyth...

The country north of USA targeted a certain group and took their funds earlier this month. https://www.insurancejournal.com/news/international/2022/02/...

Decentralized consensus & trust doesn't rely on banks and all the associated cost, complexity, obscurity, and gatekeeping that comes with them. With crypto: "Banks" can't unilaterally or fraudulently print more money, settlement is much faster & public / atomic, APIs are through transparent smart contracts rather than semi-structured SWIFT messages, and no need to rely on trust that funds are real compared to (say) Eurodollar derivatives -- i.e. many of the legacy hacks that others are talking about in this thread.

Which is not just a number on a computer, right?

ITs a number of lots of computers that use crypto algorithms to decide what the True ledger is.. So it cant be edited like a row in a DB can. But yes. you're right.

That's right. Bitcoin is represented via 10-minute sequential hashed blocks. You can't forge that currency without re-doing 13 years of computing work.

Unfortunately many won't until they find themselves in a circumstance where decentralization is of vital importance. At which point it may be too late.