Can it work for this use-case? I have lots of 15 seconds to 1 min duration videos) of my kids and want to upload them all (let's say 10 videos) and have the agent make a single video with all the best bits of them?

yes! you can upload as many videos as you want (file limits currently are at 20GB and 90 minutes, per file). then I'd recommend using either the Rough Cut tile or the Montage tile to stitch them all together. In those tiles, you can prompt particular visual cues in terms of how you want the videos to be combined. Let me know if any questions.