hey lucideer, I think it's usefull when you had to work with SVG sprites + React.
Converts the attributes not supported in React (xlink:href, fill-rule, etc.) to valid React attributes and also in case you have inline styles (eg. style="margin-left:20px") this tool will generate a Javascript object from that style ({marginLeft: 20}), which is valid React inline style.
Also, I think it's super usefull in case you had to use an inline SVG exported from Sketch or AI
I quickly tested it before commenting above and it stripped and discarded quite a lot of my SVG code (hence my comment on lossy transformations). I've just looked into React's SVG support and it is poor and hacky (e.g. it hardcodes two ns prefixes rather than supporting aliased uris as per the SVG spec.), so I guess my main objection should really be with React's (lack of) decent SVG support rather than with this tool.
That said though, I've used SVG in React quite a lot myself, but I've always opted for SVG as strings or external static resources rather than inlined vdom objects - this has worked fine for me as I would think of SVG as a display format so it has never needed granular access according to application state in my experience.