Not really.
In the last year, the US dollar actually increased in value 10% against the Canadian dollar, increased 12% against the Japanese yen, and increased 20% against the Australian dollar. It decreased 1% against the Euro, decreased 3% against the Swiss franc, and decreased 4% against the pound.
In gold terms, the US dollar is 39% more valuable today than it was a year ago.
I also put some money into crypto-currencies, though not because I fear the imminent collapse of the dollar. The dollar's value has been pretty stable even through the financial collapse.
Dollars seem perfectly fine for transactions, though no currency is suitable as a store value for decades or generations.
https://en.wikipedia.org/wiki/Currency_War_of_2009%E2%80%932...
Bitcoin doesn't have enough of a track record to make predictions about how long it will last.
I bought Bitcoin and other crypto-currencies not as a long-term store of wealth, but for their other valuable qualities.