I agree. It makes me remember that each time I installed a nethserver mail server I noticed that the effectiveness of the filter wasn’t so good at first time, especially for spams in another language than english. This is because the Bayesian filter doesn’t kick in before it learns 200 hams and 200 spams (wether you use SpamAssassin or rspamd). We discussed this with @filippo_carletti a long time ago and for sure it wasn’t that clear.
Therefore it could be useful to display a message to prevent disappointment and to keep user form being tempted to fiddle with the standard rules (that works good out of the box indeed).