Of all of the options for storing photos and videos in the cloud, Google Photos is the only one that I know of that provides a bulk download option. Other cloud storage services let you bulk upload your media but downloading is a labor-intensive manual process. This makes it difficult to create an off-cloud backup of your media or migrate to cloud storage from a different provider.
You can bulk download your media from Google Photos using Google Takeout. Google Takeout lets you download data for many of your Google services. I see from the Wikipedia page about the service that it also lets you download your Google Play Music data but I have not tried it myself yet so I do not know if that means it will let you download the songs or just the metadata.
If I am wrong about Google Photos being the only cloud storage service that provides bulk download, I would love to hear about it! You can reach me at david@sloopsoft.com to let me know. I will post an update after I verify the information.