This seems pedantic. Of course the product needs to work for some users before you can measure anything about it. Otherwise your dashboard is filled with zeros, which should be obvious because the product doesn't work for anyone (and isn't a product).

Once you've gotten to the MVP stage, you should be tracking the key metrics, and those should be easily viewable in some sort of dashboard. Tracking up-time (or if the service is working) is a small part of what should be measured. When you're just starting off, you need to quickly figure out if your market hypothesis is correct. You can't do that without data, and a dashboard is both easy to build and helps make more informed decisions for everyone involved.

No one is arguing that you should build a dashboard before you have a MVP. Once that happens, you need to be measuring things.