I just ran across some recent stats on the benefits of using drone video in an article on RISMedia.com:
According to MLS statistics, homes with aerial images sold 68 percent faster than homes with standard images. Video tours that incorporate drone footage are also a great way to make your property stand out and to attract new listings. According to the National Association of REALTORS® (NAR), 73 percent of homeowners say that they are more likely to list with a real estate agent who uses video to market their home; however, only 9 percent of agents create listing videos. An Australian real estate group reported seeing a 403 percent increase in traffic for listings that included video as compared to listings without.
The article has a lot of good stats that real estate photographers that offer drone services can use for your marketing materials.