Interesting that two of the reports linked to on that news site didn't use the official Google charger when the battery caught fire. Perhaps not related to these specific fires; I suppose plenty of people use off-brand chargers instead of buying the official one (which comes at a premium price, at least where I live, so it's not far off to say that off-brand chargers are probably more popular).
From one of the reports on Reddit:
I was just woken up by my pixel 6a fully in flames on my bed, while it was charging.
[…]
I have a smoke detector that's tested regularly, but my building does not have them installed in bedrooms, only in communal areas. There is one right outside the bedroom door.
Lucky for them that the smoke detector wasn't too far away, although can obviously save valuable time if a detector is in the room where the device is charging. Also seems risky to be charging a device while it's lying on material that can easily catch fire.
Obviously it's not their fault that their device caught fire. I wasn't very aware myself of the risks of batteries catching fire until I read my local fire department's advice on phone charging. Apparently they recommend to not charge phones during the night, in case you don't hear the detector go off and won't be able to react quickly enough. I'm assuming that also applies to charging while people are absent from the apartment, for quite obvious reasons, although most people carry their phones with them when they go outside and don't leave it at home, so that's probably less common.
They also do recommend to use the charger that comes from the device manufacturer instead of an off-brand one. Obviously there are high-quality off-brand chargers, but I think lots of people buy cheap, poor-quality ones so it seems prudent for them to just advice against using using non-official chargers entirely.