Works quite well. Input images must have geo data in the exif metadata like longitude, latitude, FOV, camera pitch (most drones e.g. Autel and DJI drones will include this). You need to set it up on a server, then it's a web app which you could access from a phone/tablet but it involves uploading the images so it probably won't work well like that.

But I'm sure you're aware of https://qgis.org/en/site/. Some of my friends used this to analyze vegetation using drone imagery.