Some people compare it with that flower thing that went viral in past. No logical connection can be made between these two, bitcoin has real life applications.
Of course it has real life applications and has been accepted by a large number of companies and countries across the world. Practical life applications like making the transfer of funds across borders and using it as a medium of exchange have made lives easy.
If it were a bubble, it would not have captured a big portion of the market and a big market cap. Besides, in any market, as long as you have the costumers, you are the one who would live long.