I am the Director of User Experience for several large companies. I make an interactive prototypes for them. These companies are doing mostly Web, AR and VR applications for global audiences. That being said almost all of the applications are made with 3d animations. The limit of 20 mp4s per document will not allow XD to be used for designing this type of software because the transitions from any point in the application need to me animated footage for a seamless experience. If you want XD to be used by big companies that are designing heavy software applications in AR, VR, and web based, then the Mp4 count needs to be higher. (or doubled)