This is an interesting example. The wiki said he was worth $200B at his death, while his boat cost $200M when built. When he died it sold for 230M. So in a sense it was an asset, in that it did not depreciate (ignoring inflation). Though I’m sure it cost a lot to operate and maintain.

So he spent 0.1% of his wealth on this! Pretty reasonable budget to spend on something you enjoy IMHO.

He also put it to use on some exploratory missions, rescue mission etc.