UPDATE: I'm in Denmark (EU). On nintendo.com, I don't get a "Buy digital" button. If I go to the region-specific site nintendo.dk, the search function is broken, many games aren't listed, and there's no buttons to buy games or any login functionality at all (it seems half-baked). If I go to nintendo.co.uk (the UK site), I can log in and buy digital, hurray! What an incredibly inconsistent experience!

What region are you in?

In the US it clearly gives me the option to buy a digital copy: https://i.imgur.com/dIbfnjP.png

I don’t know what to tell you; I get a great big red “Buy digital” button just to the right of the price if I go to that page.

Edit: Australia, here.