Bitcoin can become useless only if people stop using it for some reason. In the short term, this seems unlikely, because not all people yet know what a cryptocurrency is. The technology of digital money is convenient, practical, has cheap transfers, therefore the society perceives it positively.
It can be useless at any time. For instance, imagine the situation when you own Bitcoin, but for some reasons, you find yourself in the place where the Internet connection is not available.
Exactly, you can't do any transactions if you are in such place where internet is not accessible, same with if you are inside the forest even you have all the
fiat in the world you can't used it in anyhow, if the in the real essence, bitcoin will not be worthless as it's already have a value.
bitcoin become valuable not only due to its function as currency.but it bring new technology and breakthrough in finance industry.bitcoin bring new concept where anyone could make transaction in more effective ways with less transaction fee.its about new technology in payment gateway.