Pewter mugs has gained popularity because of the price of silver jewelery has gone up. They have the look somewhat similar at first glance. Pewter mostly tin, a soft metal. Previous manufacture of tin is used as one of the lead alloy, but fortunately this practice is becoming rare, at least in the United States.
In earlier times pewter hardware is what people eat with. Dishes and pewter mugs in the Middle Ages all the way up to the 18th century and 19th, especially tin, before porcelain came into its own. I imagine this early pewter full of leads but I have not heard a lot of trouble because of it.
Does pewter jewelry made in earlier times? I believe it is, but because of the softness of the metal, and the ease of which can melt and punished other uses, not much has survived. It’s possible the Celtic people made their famous knot designs in pewter. But how pewter mugs are modern, and what would be the advantage of silver? These are all good reasons. I would add that the fact that the tin can be every bit as detailed as the finest silver jewelry, and when properly throw and finish, virtually indistinguishable from it.