Cherry trees all across Japan (not just Kyoto) are blooming earlier and earlier
and this confirms that the trend cannot be explained by local urbanization alone c(https://gizmodo.com/japan-hasnt-seen-cherry-blossoms-this-ea...). However, Kyoto's transformation into a dense urban environment has for sure made the local signal worse.
This is what rquickshare documentation says: "Wi-Fi LAN only. Your devices need to be on the same network for this app to work." So no, it's not an AirDrop replacement.