My personal take on this is: "ImageMagick is Sendmail/Bind/OpenSSL class of software - unlimited, constant and guaranted chain of CVE's and other kind of bugs with proven history of that (year by year, often each month of the year) since the dawn of times and most likely with forever continuation of that track record. And no plans of changing trajectory."
If GraphicsMagick is better than that, then it is clearly a benefit of having it around.
IM is easy to sandbox (I myself have a bwrap profile for it) and GM is abandonware; it's basically ffmpeg vs libav. VIPS is where it's at if you want to know about the future.
If GraphicsMagick is better than that, then it is clearly a benefit of having it around.