How does having a Delegated convention vs One-Member-One-Vote change the results of a leadership convention for political parties? [closed]

Is one of the systems fairer ? What is the purpose of these systems? For eg. FTTP produces stable majorities whereas PropRep represents voters better but leads to more elections. How do these systems for internal party conventions affect results ? What's the intention behind doing them one way or another ?

Here is how a delegated convention works(This is regarding a political party in Ontario, Canada): https://www.cbc.ca/news/canada/toronto/ontario-liberal-leadearship-race-convention-1.5488453

The majority of delegates are elected at the constituency level and
are already committed to voting for a particular candidate on the
first ballot. There are also several dozen independent delegates and
some 640 ex-officio delegates — which include people who have held
positions in the party like former and current MPPs, as well as
Liberal MPs and other heavy hitters — who can vote for any candidate
on the first ballot.

A candidate needs more than 50 per cent of delegate votes to become
leader.

This is similar to what the Democratic party has. However, other parties in Canada use One Member One Vote. Where contestants of primaries have to sign up new party members before a deadline. On election day, only registered members can vote and determine the leader.