I think the bitcoin price is more important. It means it is taking more market share from bitcoin.
Depends if you're trading/gambling to try and use alts to build up your bitcoin stash, or investing long term in the overall crypto-currency concept.
Pricing in dollars is basically a measure of the total value that *all* crypto, combined, is absorbing from the old-world, dying, fiat-currency global system.
Both measurements are important...