As I understand it, the point of the explosive is to have finer control over when the fuse blows. An ordinary fuse is more or less a resistor, and it blows when

As I understand it, the point of the explosive is to have finer control over when the fuse blows. An ordinary fuse is more or less a resistor, and it blows when part of it gets hot enough. There is a fair amount of error, and this means they work best when there is a considerable margin between the current they must carry without blowing and the conditions under which they must blow. Conventional thermal-magnetic or hydraulic-magnetic circuit breakers are similar. AIUI some high performance cars may draw so much current under maximum acceleration that the fuse needs to be dangerously large to avoid blowing when flooring it. The solution is an electronically triggered fuse. A reliable and precise electronic circuit detects excessive current and blows a small pyrotechnic charge that opens the fuse. The analogous technology for circuit breakers is fairly mature in the commercial/industrial world — you can buy an electronically tripped circuit breaker, and there is likely one in an office building near you. (Electronic trip devices for circuit breakers have ludicrous list prices, and there is no way a car company would pay anything resembling those prices for a car component that lets them eke out a bit more performance. I bet Tesla’s cost for its pyro fuses is quite low.)