Consider the situation where, very early on, a candidate locks up sufficient delegates to win the nomination. That candidate does something to self destruct making it a virtual certainty that they will not win the general election.
If the candidate doesn't withdraw, the party faces certain defeat. If the candidate does withdraw, the party risks putting an untested candidate on the ticket.
Spaced out primaries are a good training ground for the general election. The also ensure that the cream rises to the top slowly and is not boiled away in a flash of steam.
Garde la Foi, mes amis! Nous nous sommes les sauveurs de la République! Maintenant et Toujours!
(Keep the Faith, my friends! We are the saviors of the Republic! Now and Forever!)
LonePalm, le Républicain du verre cassé (The Broken Glass Republican)
What-uh-you, sime kind uh French chef?