I used to work with someone who had a message telling people she only checked her email twice a day. You pretty much needed to call her if you needed anything outside of those times. (She worked in a remote office.) I think she had read one of those books on efficiency that recommended scheduled email time. But there were problems with this: 4. My department often had to email attachments or text to illustrate our questions/concerns. And we were on deadlines. Reading a page of text over the phone was not an efficient use of anyone’s time 5. She did outreach & was often out of the office on site visits, trainings, or travel to these places, but never ever set her OOO for these, because she was “working.” However, she was effectively not available to read emails from other staff until after hours on those days.
To be honest, if it wasn’t for the bloody flashing red light I’d never bother with it. Can’t stand the flashing light.

Yeah, it’s very strange. I understood changing voicemails to explain that the line can’t actually be answered, but someone is checking the messages and will respond (though that was also only an issue for the first few months), but they had no reason to even mention it for email. I started my job 3 months into lockdown, and by that point, procedures were in place to pretty much allow us to operate normally, albeit with a lot more done electronically than before.
I still hate that lady. She made one of my coworkers cry until she had to leave work because it turned into an unstoppable panic attack. I later had one too.