Once you accept that currency has value because it is useful, you have to accept the implication that financial transactions have utility as well, because they are necessary, integral, to the operation of the currency, it's growth and efficient discounting.  When we account the GDP of a nation, we do not exclude financial transactions.  No more should financial transactions be excluded from considering the economy of XMR.  Financial transactions are a form of dealing in intellectual property.  Unlike a movie or a book, this intellectual property has productive material use.

The non-financial portion of the XMR economy is growing much more rapidly than did the non-financial portion of the BTC economy.  Often this will not be visible in XMR because transactions are vastly more private, so proxy methods must be used to estimate their scale.  I would very much like a payment gateway which enables me to transparently use XMR, to send to a BTC address, and to receive BTC in the form of XMR.   It's a relatively simply thing to implement, and makes it more practical to save primarily in XMR.