I think having the date in the URL is primarily useful if you're writing news articles that pertain to events of a specific day. Let's say that in 5 months from now, someone is searching for a headline that they know happened on March 21st, 2018. Having 3-21-18 in the URL could be useful to them as they know that your article was written on that day.
However, for most blogs that are trying to bring in users months and years later, especially when the articles don't pertain to events of a specific date, having cleaner URLs is more likely to help you.
A lot of bloggers are trying to hide their publication date altogether. The reason for this is that most people searching on Google aren't as likely to click on an article that was written several years ago as they are looking for a current source for their information. And bloggers are usually trying to have their articles rank for many years. Showcasing your publication date in the URL could potentially lead to declining click throughs in the future.
So in most cases I would prefer to have the cleaner URL.