If you hold bitcoins for around five years, the original price might double or triple or even be ten times the original, on the other hand if you hold dollars for 5 years the price won't increase enough to make you a profit like bitcoin does.
Agree, if you hold bitcoin even for a long time there will be a profit and your money will grow, but in dollars your money is still the same. The bitcoin is increasing its value and you can use anywhere around the world and you can use it through online for payments or billings not like in dollars it cannot be use. You can also invest and buy some coins and you will earn profit for the next many days.