It all depends on how one includes the SVG into the HTML document. If one uses:

• <img>: when referencing the SVG's file with this tag it will be indexed just like any other image. Hot-linkers other than Google can and likely will hot-link your images.
  
• <svg>: when embedding the SVG directly into the HTML the image will not be indexed in Google image search and cannot be hot-linked
  
• <object>: when referencing the SVG's file with this tag Google does not include the image in Google image search. Technically (I believe) hot-linkers should be able to hot-link the files but in my experience they do not.
  

Thanks for your answer.

Do you know if Google is taking in consideration the text which is embed into a SVG file, for ranking the "image"?

Hot-linkers and scrapers are two different things. I am fine with hot-linkers, I can more or less control what is showing (or not) at other sites, and now that Google has refined its Image search algorithm to take in consideration authority of sites, I am confident that hot -linkers will no longer outrank the sites from where images are originally coming from.

I am more concerned by scrapers , those who download images, and serve their own copies. Do you have any experience on the subject? Do these image scrapers are only downloading bitmap files?