The law is enforceable. If the options you’re given is “put a backdoor in your product or stop operating in the country”, it’ll happen. And even if you reply “then I’ll go away”, laws like this, stupid, dangerous, breaking everything, will keep popping in one country after another until it’s too late.

It not making sense have no bearing on whether it can be enforced or not. And the mere existence of the law may be enough to later put you in hot water if you have some de-facto illegal software on your phone or computer, for example. It would not be automatic everywhere, but another tool to just legally have something against most people.