Ranked in these QuestionsQuestion Ranking
Pro Can be set to auto-upload images
Flickr has an app on Windows, OSX, iOS and Android, called Flickr Uploadr (available for download in the tools section) that can automatically upload images to Flickr. It can even pull images from external drives and other cloud storage services such as iCloud.
Pro Photos are backed up elsewhere
I mainly use Google Photos and keep separate local backup of all my photos, but also use the IOS app which transfers all new photos onto Flickr storage as well.
Pro Good search
Flickr is capable of searching images by a combination of content, color, shape, depth of field, style, pattern, size, license and other options.
Pro Built-in image recognition
Flickr will automatically attempt to figure out the contents of a picture and tag them appropriately. This will allow you to look for, for example, all images of flowers, bridges or butterflies.
Con No offline view
While Google Photos and iCloud Photo Library allow you to select if you want to keep local copies of your photos, Flickr only allow you to view your photos online.
Con There are limits on file sizes
Images can't be more than 200MB a piece and each video can't take up more than 1GB of space.
Con No support for lossless file formats
Photos can only be saved as .jpg, .gif (non-animated) and .png files.