The question/bug is not whether a "what's new" button is useful - I'm sure it is to some people. The bug is that it can't be customized, i.e. removed from the toolbar, just like all other buttons.
Bug 1589225 Comment 4 Edit History
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The question/bug is not whether a "what's new" button is useful - I'm sure it is to some people. The bug is that it can't be customized, i.e. removed from the toolbar, just like all other buttons. My first reaction was also to open customize to quickly get rid of it, only to find out this doesn't work.