Privacy and significant location & Routes

You are combining 2 different things that are really unrelated in your Context. The Map data whether you are viewing it in Significant Locations or in the Maps app has the Legal link that tells you where the data comes from and has nothing to do with the Significant Locations on your device. None of the sources in the Map Data has access to your Significant Locations for any Privacy Concern.

Specifically for your Significant Locations, that is data that your device uses for suggestions when using the Maps app and not even Apple has access to that data as you can see in your Screenshot. Your device is not a Personal Tracking device, so you will not see every location you have visited and that too is for your privacy protections.

There was a time when the Significant Locations were visible on the device, but that could lead to situations where a spouse or anyone that has access to the Passcode of a device could use it to see exactly where that person went and the path they travelled. It was due to privacy concerns, and frankly safety, that it is now not visible, except for the very limited Recent locations and those are not even in chronological order to show last location or determine any path. There is no legitimate need for you to view all the Significant Locations, but there are uses for it on your device, not only for Map Suggestions, but other features as well like Stolen Device Protection.

You are overthinking it, but it isn't entirely clear, so it's worth asking.

Ultimately, you're looking at two different things.

Significant Locations are points of interest that Maps has weaned from your use - places you go, places you spend time at, etc. Most obvious examples are your home and workplace, but your favorite coffee shop, restaurant, movie theater, etc. could also be added over time, once Maps determines a pattern.

The list of hundreds of other web sites, etc. is completely unrelated to your Significant Locations. For obvious reasons (mostly because the world is a big place), Apple do not launch their own satellites, survey every street, map every house, visit every business, or photograph every building in the world. There are other companies out there that do that, and Apple buys the right (via a license) to use that data as part of the Maps service. Consequently, under the terms of that license, Apple acknowledge where their data came from. For example, in your screen shot:

You can see that Apple is including business listings from (at least) Bookatable and Booking.com. These sites have directory data about businesses (address, phone numbers, hours of business, menus, reviews, etc.) and Apple uses that data to enhance the Maps experience (click on a restaurant, for example, and Maps will tell you their hours, based on data from one of these companies). This saves Apple from having to do that legwork of visiting the businesses, and keeping the data up-to date.

That is in no way connected to your Significant Locations. Booking.com doesn't get to see your 'Home' or 'Work' location. Yelp doesn't get to see your dining preferences, etc. (well, unless you follow a link through to Yelp and make a reservation :) ).

So all of this is due diligence on Apple's part, giving a nod to the companies that populate the Maps ecosystem, not some broad conspiracy to share your location preferences.