Which is why it's bad writing.
"Unblockable killing spell" is the kind of thing that pops up on a middle school playground because every kid wants to have the trump card in make-believe and the last kid just cast Meteor.
Eragon is a contemporary-ish book and has killing magic that can kill normies by the dozens/hundreds, but other magic users have to do more than play rock-paper-nuclear-option.
Registering is fine, a lot of people voluntarily register their expensive bikes with local police that have those programs anyway.
Insurance is weirder. Cars require as much insurance as they do because they weigh multiple tons and can kill people and destroy infrastructure. A powered bike can do a lot of damage, especially if it rams someone, but it has an order of magnitude less destructive potential than a car. Especially for a limited powered bike insurance "should" be significantly cheaper.