In accounting, a loss is an asset - as it can be used to reduce future (paper) profits to pay less (actual) taxes. This wasn't a deliberate strategy though, but rather the automatic application of applicable regulations (mark to market).

Tesla didn't sell any BTC so in reality they didn't lose anything. Also, they weren't 'trading' bitcoin - they bought and (mostly) just held.

It's a clickbait article. Try and avoid anything that says "web3".