Large C++ files are bad. Large Blueprints are far more worse.
The larger a file is, it usually ends up being harder to read and maintain. It is likely it could easily be split up into many different objects.
Blueprints are even worse because they are even harder to read and are binary files (making them a nightmare for VCS).
But for small projects it probably doesn’t matter. Just think to yourself, would you benefit in anyway from splitting it up? Could this part of the BP be used by another BP?