Anglo evangelicalism constrained its meaning to something like "intellectual assent", for its own purposes (in my opinion, it made for better sales models) some time in the nineteenth century. And as you essentially point out, intellectual assent is fairly meaningless.
Unless you live in a brutal theocracy, it's difficult to describe just how powerful institutionalized Christianity was at the time. Likewise the scale of religion-themed violence. A couple generations before Pascal's birth (in France), the Catholic-vs.-Protestant https://en.wikipedia.org/wiki/French_Wars_of_Religion had kill off something between 10% and 25% of the population of France.
Pascal's own religious beliefs changed several times - https://en.wikipedia.org/wiki/Blaise_Pascal#Religious_conver...
The Wager was published after Pascal's death, in an edited collection of his notes - https://en.wikipedia.org/wiki/Pens%C3%A9es
In many ways, I'd interpret the Wager as saying "if professing quiet belief in the current local orthodoxy is relatively cheap, and those not doing so are occasionally slaughtered at scale, then prudent people will parrot orthodoxy".