PMQs is an opportunity for MPs to put questions to the Government, in public. If the government chooses to publicly dodge a legitimate question, that in itself is worth it.
Before Blair, PMQs were twice a week for 15 minutes. Once a week for 30 is a recent change. And before Wilson & Heath it was pretty civilised. That too is a recent change, and it’s got markedly worse under the recent run of Tories.