All of these services and tools are ultimately about automating boring, repetitive work. With algorithms like SSIM, and libraries like Butteraugli being available for the better part of a decade, it has been possible to reduce the overwhelming amount of switches and toggles that image optimizing tools provide with the user-friendly alternative of “make this as small as possible, without changing how it looks”.
A feature examination was done to see if this was something offered. As this is, by its very nature, very computationally expensive, it was not expected to be performed by default. But rather as an option that a developer can enable should they desire.