Maybe Reformation religions require belief, but the paganism was a set of rituals known to work (by virtue of having worked before), sort of a like a spiritual experimental science. Belief was not required.
Religions don't necessarily work because people believe in it, either. There are a number of religious sects that started with end of the world prophecies.
I think that religions work the opposite way: people believe in them because they work. Since the purpose of religion is generally to explain the nature of reality and how to flourish in it, it needs to work for you. If it doesn't, you either just go through the motions, or quit and find a different religion (or swear off religion, which is sort of the same thing).
Reminds me of Julius Caesar describing the druids. Part of his political career meant precisely performing important orthopraxy. He probably didn’t meet a druid, but amazingly described them playing the same role he did as Pontifex Maximus.
The orthopraxy requiring those precision rituals, take Rome and Greece, had little or maybe no mandatory beliefs. City-state-sized gods in Mesopotamia probably functioned the same way. Traditions still have precise orthopraxy today. But we talk about differences in belief whereas Caesar doesn’t even acknowledge any.
Charitable read, would suggest slight touch of tongue in a cheek.
A bit of spelling it out
Point-1. People just interpreted that paganism works.
E.g. Somebody made offering to gods, and year later won a war - proof.
Point-2 paganism had this transactional notion with gods giving and taking based on your offerings.
While christianity on the other hand does not promise anything good in this life (the only promise being: bear all the bad things in this life, you will be rewarded in the afterlife), so there can’t be proof.
