See also this thread to know where the Stock Media files from the Hub are stored.
For your second question, once these files are downloaded, of course you can use them in whatever program you want. You can put them on your phone and play them back on your car radio, if you want. When you create a video with a video editing program, it doesn't matter which program that you use and the program that the video is exported from is usually unknown. However, what you do with the exported video may have concerns, particularly if you monetize the video on YouTube. You will most likely get a copyright claim that you can contest.
Here is what the on-line manual for Video deluxe 2027 says:
Magix Content gives users access to an extensive library of over one million items of royalty-free content, including:
Video content (stock footage, animations and visual effects)
Audio content (song archives and audio effects)
The MAGIX Content library offers an unlimited selection of HD videos and audio files that are available for use without restrictions. Thanks to our collaboration with Storyblocks, you have access to all content for any project, for an unlimited period of time – without having to worry about usage rights.
You can see this by going to Help in VDL 2027, and searching for "Stock Content."