I respect your point of view when it comes to bitcoin. It wasn't entirely useless if a lot of people are benefiting from it. A lot of people get rich because of bitcoin and I think it is quite rude to say it was useless.
yes i agree with you, maybe that person dont realize the worth of bitcoin. that person needs more proof of bitcoin, bitcoin is very useful and it never as useless. the person that may say that bitcoin is useless must prove he said.
Pessimism is against your positivity and optimism is against your negativity for those who keep such negative thoughts about any business like Bitcoin.
As you said only negative minded people can thinks such thing that is why the market is full of such negativity that has an inverse affect on the popularity of Bitcoin. Bit all these are the abortive attempts and will not get success to stop Bitcoin from growing more.