I believe the "buy and hold" strategy is not really applicable to the crypto currency world at this time because it changes too rapidly. The swings are too wild. My thought is for crypto currency, a better strategy would be "buy and sell" or "mine and trade". Buy low and sell a bit higher to make a profit. Don't be greedy, some gain is better than no gain or a loss. The end result is really trying to make some gain for each transaction.
The other strategy is to "mine and trade" - mine a crypto that has a relatively high value and low difficulty and trade it for another crypto with higher potential, and yet more difficult to mine or cannot be mined. Even though the coin you are trading for may have a lower value now, it doesn't mean it's not better. Always evaluate a crypto based on it's primary function and the team and projects behind the coin. Another food for thought is trade your mined crypto for some stakeable coins, so you are building up your assets base over a longer period of time and hopefully one day, you can be a masternode. At that time, you are in a position to reap dividend and just let the money works for you and not you working for the money.
Cheers!
RE: Strategic Advantage: The right time to Buy Steem and Bitcoin