[slg]

Yes, at the most general level highly volatile assets should be rebalanced more frequently. However, that isn't going to be a universal rule. It will depend on what is causing the volatility and whether that is more a product of the market or something specific related to the assets. Rebalancing too frequently is also a very real possibility so more is not always better.

Another consideration specific to cryptocurrencies like Bitcoin is the relatively high transaction fee. You don't want to see your investments be whittled away by frequent transaction fees doing unnecessary rebalances. I haven't spent enough time researching cryptocurrencies to know how all these considerations shake out when it comes to this specific index fund, but as a pure gut instinct the annual rebalancing was less frequent than I would have expected from this type of fund.

[proofofmoon]

Rebalancing cryptoassets on the same exchange (without withdrawing to a wallet [1]) doesn't require on-chain transactions. The fee would be the order fill fee, which for GDAX is 0-0.25%, much less than 2% of the account balance.

([1] For the not-your-keys-not-your-coins crowd: if you don't trust Coinbase with the coins, you can't trust it with the fund either.)