That JQuery API is used only for the front-end elements, particularly on handling events and manipulating it on the website -- the way how they receive the price input of the user and how they show the results. Apparently, they've used the google API so that the user would just use an online jQuery file than getting it from the website's server, but using it doesn't really tracks you down. And yes, Google API's for some front end development (such as using online Google fonts) never tracks any user, but rather just sends data without receiving one.

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I like the idea of the project. However, just like Vod's have mentioned, you can use referral links to have at least a little monetization to your platform, or you can have 2 options where they can choose one with ref link or without (for a better user preference). And I would also like to suggest to add more supported exchanges. For the front end, there are other ways to visualize results that would fit  for a better user-experience, but yours doesn't really need a change at all. Good job!