It's hard to say that the webinars have been devalued based in my opinion. For example there has been a mix of 3 and 5 Club Point webinars in the past with the first 3 Club Point webinar making its appearance back in Oct 2021 (if you click or tap on the table below, it becomes more readable).
Also the 2025/2026 Deployment webinar in December and credited in January 2024 was a 5 pointer so they are still around.
What is hard to tell is why one webinar is worth 3 points and why another is worth 5. I don't think it is webinar length and when you scan the list, a clear pattern doesn't emerge to me.
The dates in the table below represent when the points were credited and not when the activity was performed. The table has not been updated to include this month's webinar that should be credited against April.