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.
You might receive multiple emails from coworkers and clients if you’re not specific about your absence dates, which will clog your inbox and make it hard for you to remain productive when you get back.

There ought to be a word - and perhaps there is, in German - for the mix of feelings that accompanies composing and activating a holiday out-of-office message. There's smugness, of course, and a gratifying sense of laying down one's virtual tools after a horribly long shift. But for many of us, these nice feelings are tempered by the knowledge that in two weeks, refreshed but depressed, we will have to trawl through hundreds of emails, many of which will be conference room notifications for meetings about crises that have passed.
I have a coworker who has an “always-on” autoreply stating that she “is busy with client meetings during the day” and therefore only checks emails at 9am and 3pm. I understand wanting to set the expectation that people won’t get an immediate response, but it really baffles me. If you are still able to respond within 24 hours, why does anyone need this information? To me it feels like some weird self-help tip or power move that they read somewhere that serves no actual function.