The main benefit from baptism actually happens directly after…the conferring of the Holy Ghost.
Baptism is a prayer - You state the person’s full name, your authority, say that you’re baptizing, and close in the name of Christ. It’s a word-for-word prayer that must be done right or over again until it’s right. Each repetition requires a new dip for the baptizee, and the dip must be right as well or done again. (ALL the way under, not even hair can float.)
They used to confer the Holy Ghost in Sacrament Meeting on the Sunday following baptism, but some people weren’t serious and didn’t show for the second part. So now they give the Holy Ghost blessing right after the baptism.
The Holy Ghost blessing is a little more free-form. Full name, authority, confer the Holy Ghost, and then…say what you
think feel The Spirit wants you to say. People get promised wild shit in these blessings sometimes.
“Having” The Spirit is a big deal, because it speaks to you in “a still small voice” and helps guide you through life. The poor saps without The Spirit are on their own.
Pointing out that you could live a life of debauchery, and die, and accept a baptism for the dead in the Spirit World, is frowned upon.
ETA - Also, baptism is the “strait gate” from the New Testament - You’re not a member until you pass through the gate. Being a member of the Church and having The Spirit are the two big motivators for baptism.
(Light edits, sorry.)