There's no reason they wouldn't be edible. Things are usually inedible because either they have some compound that's meant to be very durable (lignin in wood),

There's no reason they wouldn't be edible. Things are usually inedible because either they have some compound that's meant to be very durable (lignin in wood), they have evolved to be poisonous (many plants and fungi). A H2-eating microbe probably has no reason to evolve either property.