I'm working on a landing page for a private taxi.
The desired action on this page is to make a phone call.

Now, there's a big phone number and a small script to track the clics on it.
That works well for mobile users, but this design doesn't allow me to track calls made by desktop users and tablets users. I want to keep the original phone number and do not want to use another number provided by a service specialized in phone call tracking.

A solution would be to use a button with a CTA. It would reveal the phone number when desktop users clic on it and make the phone call for mobile users. Users would be forced to clic on it if they are interested.

To complement the main CTA ("call now"), a link to download the card could be added to the page and would be secondary objective.

I would like to have your feelings about this idea?

Do you think this idea is too frustrating for the users if there's no phone number on the page at a first look?