We even find ourselves creating PRs in situations where the code is going to be merged immediately anyway, and tagging other devs, just so they have a convenient way to see what got merged and why. So people don't lose track of what is in the codebase.
this is a great way to train people to ignore PR emails/notifications
It's a good practice. Worth mentioning also: the same can be done with ordinary git log, assuming everyone is using git well. A proper git log of yesterday's work can be like your work newspaper with coffee.