I'm surprised this unauthorized method uses the API at all. Years ago I animated a route with streetview images using crude browser animation and screenshots.
I automated clicking the Streetview arrow in a browser and taking a screenshot of a defined region of the screen to create a type of Streetview Hyperlapse. Many other tools have done it better since, at least as far back as 2013: https://tllabs.io/google-street-view-hyperlapse-youtube-vide...
Going back to your first comment, I originally made this as part of an app with an interactive streetview component. I reused the initialization code I had as the base for this. Re-using that code also makes sure the screenshots taken would be close as what you'd see using the embedded streetview (In our project we had a bunch of remote locations without a lot of SV images, so depending on the search radius used when querying for a panorama, we could end up in vastly different places).
However, I realize that I never even considered scraping the public site, which would allow for hiding your identity by not needing an API key. I'll think about this.
[0] https://loichovon.com/posts/streetview-scraper-v2.html