Allows the full syntax of the 'filter' property to be used on SVG elements which previously only supported single url(...) references. This allows filter functions such as blur(...), sepia(...) and grayscale(...) to apply to SVG elements as well as non-SVG elements. It makes the platform support for 'filter' more uniform and allows for easier application of some "canned" effects.
Without this feature developers need to use a full SVG <filter> element definition even for basic filters like grayscale(...) or blur(...).
Samples: https://css-tricks.com/almanac/properties/f/filter/