Why convert the starting scout to a prophet in turn 1

[Squirrelloid]

There are other rationales for prophetizing the scout.

You have a nation for which every priest can reanimate. Making the scout your prophet gives you an H3 reanimator from turn 2 without slowing down your expansion.

You want stealth preaching. A unit with sneak and Hx can preach while hiding, allowing you pinpoint targetting on dominion spread, possibly in a dom-kill attempt. And he gets his prophet dom-spread check as well. Speaking of...

You want the prophet dominion spread check right away (and need to do something else with your commander).

Your scout is your least useful starting or otherwise early unit, and therefore you suffer the lowest opportunity cost by making him take an action to become prophet. (Basically, most people want the H3 caster as their primary reason for making a prophet, especially in the early game. The fact that he is permanently blessed and gets a hp-multiplier/divider based on dominion will be useful much later, but in the early game its not significant). The opportunity cost involved in killing your prophet is also much lower if your prophet was your scout. (Allowing you to more easily accept suiciding him to make some other specific unit a scout).

(Not to say that scouts aren't useful, but they're only useful in quantity - one scout is not very much intelligence each turn. And generally having scouts in quantity means you've found one or more indie scout recruitment sites, so your starting scout is not going to contribute notably to a spy ring).