But if you have (through whatever process) sent them a complaint that, say, "it doesn't work right using Firefox X.Y running on Windows 7", then those release notes might in fact be interesting to you. So there actually is a reason for you to be able to see them. Not for them to get in your way, though. 99% of the people won't care.

99% won’t care, and 59% will find the what’s-new popup actively confusing, distracting, and hostile. Bad trade.