Is there a potential downside? Yes. Just because a search engine sees something as Creative Commons doesn’t necessarily mean that it is. Here at MakeUseOf, for example, we’ve had at least one photographer threaten to sue us over an image he didn’t realize he himself licensed as Creative Content. He backed down when we pointed this out, and it’s one example resulting from thousands of blog posts spread over a decade, but know that this isn’t without risk.
I liked it for the simple inserting of visual effects for creating newsletters. Pictures do enhance communication and the ease of using a word document and gathering an image made this task easy. Now having to go outside of my document to find the extra spice my documents need makes this less fun. I have always used animated images that were less than artistic but were entertaining. Like others I will miss this service, but I understand progress is not always comfortable.
This is TERRIBLE! Besides being able to edit vector images like Will mentioned (which is important for those of us who don't have graphic artists available to create custom images or the budget or time to buy that service ad hoc), you could also search for style "families" (different graphics that were all in the same style). There was a huge range of files and styles in the collection and it was much faster to find what you need than to do a Bing search. Plus, you knew that everything there was free and free to use, without having to worry about CC license issues.