Statistically this seems much less of a big deal for the US than for elsewhere.
Total number of fatal snakebites per year, worldwide: 138,000 (article points this out).
Total number of those in the US: 5. (Not 5%; 5 people.)
If you can get to any decent hospital within a few hours after a bite, you'll probably live. If you're one of the unlucky 5 who cannot, then yes this pill might be a good idea.