I usually prefer spruce gum (one has to get just the right consistency, or it becomes a sticky mess that stay in your teeth for hours), or black poplar buds - especially if I have a sore throat (analgesic and anti-microbial) - but birch has its uses. That birch bark tar is supposed to be a reliable adhesive for many things and would likely have been manufactured in significant amounts for other uses. Haven't got around to making a batch here yet. I do have a pot of chaga (birch fungus) tea brewing today.