That's a lot of questions, but AFAIK it is not vulnerable to side channel analysis. That's why the author spent time on the database search use case; you must

That's a lot of questions, but AFAIK it is not vulnerable to side channel analysis. That's why the author spent time on the database search use case; you must visit every row because you don't want an attacker to be able to segment your data at all. It would be possible to make trade-offs in that specific case, but cryptographic engineers are loathe to give the common programmer such a foot-gun.