Anytime a religion can be achieve without a significant detour out of your overall strategy, it can provide a strong boost. Thus, faith-generating pantheons are extremely powerfal in fact probably far too powerful.
Even if you ought not to spread your religion, you are more or less guaranteed to have it up at least in your capital for most of the game. Hence, you can get very capital-centric follower beliefs like swords into plowshare if you play peacefully, religious community, divine inspiration (as by far my top 3) and just let your other cities get spread and use your pre-industrial faith to either purchase 2-3 GP that you plant, such that you can purchase more great people later in the game, or purchase the buildings that other religions allow as they spread to your cities. Ultimately, having a religion, even the 5th one that you don't spread will compound into more late game FPT as well as more capital-beneficial follower bonuses selection.
On super strong faith starts like desert folklore, gems/pearls, quary based etc., if you can reasonably spread your religion to nearby CS, using pilgrimage as founder bonus and going aggressively at it in the early game means:
significantly more spread your religion to us CS quests completed
significantly more total faith generated CS quests completed
the combination of the above often means more cultural CS allies/friends sometimes leading to
a couple more total culture generated CS quests completed
All of which together mean more faith in your empire, more culture and SPs in your empire, free gifted units so that you can focus your production on infrastructure, more growth and more free happiness.
Long story short, while it may not look so strong just looking at the tooltips, if you can manage ~20-30 fpt on immortal and below by around T100-120, you will get a lot of side effets from it which you cannot perceive without playing it or well, without adding significantly more variables to the equation than just what faith brings.