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I wonder why they recommend hashing server tokens in some cases. Is it so that someone who can read the database can’t hijack an account? Or am I misunderstanding why hashing is used?

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My guess is that so people who manage to access database backup cannot hijack accounts plus it gives a good defence against timing attacks as a bonus.

More generally it protects against anybody who has access to the database, including bad actors if it's leaked.

I don't think it protects against timing attack because the common way of doing it is just to use sha256 and use the resulting hash to do a lookup in the database. This is not a fixed time operation

Suppose you used the timing attack to recover the hash of a token, now you need to compute a preimage of the hash.

Exactly that. (Hijack session rather than account: any competently designed system should require re-auth before any action that would allow permanent account takeover).

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