Difference between Meeladun Nabi and Khatme Khawajgan

The reason is that meeladun nabi is restricted to a special occasion and people regard it as necessary on that occasion. Apart from this, this has resemblance with Christianity where they celebrate the birth and demise of Nabi Isa (alaihis salaam).

As for khatme khawajgan, it is only some zikr that takes place at any time or any place. Hence this resembles any other type of zikr which is permissible in shariah. Therefore, since people do not regard khatme khawajgan as a practice that is part of deen and necessary to be done at any specific time, but rather they do it at any time according to their own convenience, it is permissible and not regarded as a bidah. However, if in a certain place, people regard it as necessary, then it should be avoided in that place.

And Allah Ta'ala (الله تعالى) knows best.