This is somehow a weird assertion.  Can't money be considered as a product by itself ?

Making a monetary tool is not that easy.  You can try using seeshells, or numbers on pieces of paper.  And yet everyone will think those are not "good" money.  Money needs some properties to be considered as a good money.

A 100$ federal reserve note is not just a piece of paper with ink.  It has some security features that prevent it from counterfeiting, for instance.  It has some value apart from its facial value.  It has some value as something that is difficult to be counterfeited.

A monetary tool is a product just as a hammer is a product.  A hammer is usefull to nail nails, and a monetary tool is usefull to exchange value and trade stuffs.

Bitcoin is much a better monetary tool than federal reserve notes.  It has much better security against counterfeiting.  It can be divided much easier.   And above all, it can easily be sent through the internet.

That's why mining  bitcoin is indeed a selling of a product or service: it's a financial service given to the bitcoin community.