Bitcoin was created because the founder satoshi wants to make peer to peer payment system.
He would use bitcoin as the peer to peer currency, so it is not a 'nonsense invention', it is make sense for me.
But i still wonder about the value of btc, why it's value is so expensive.
Payment is the transfer of something from one party to another for goods or services. Payment is not the transfer of nothing(the ownership of nothing - bitcoin). And transferring nothing, is indeed a 'nonsense invention'. Regarding value, it's a subjective concept. Throughout history, people saw "value" in many investment scams and thus wasted a lot of money for their subjective concepts. Eight years ago, a programmer saw value of two Papa Johns pizzas in 10,000 bitcoins. A year ago, people saw value of a brand new car in 1 bitcoin. So, this thing is entirely subjective. But, it cannot change the objective fact of bitcoin being the ownership of nothing and hence a 'nonsense invention'.