Advantage #1 -Video file is saved directly to your computer
There's no need to import the file from a mobile device if you need the file on your computer. Additionally, your computer will have more hard drive space than your mobile phone.
Advantage #2 - High quality, but smaller file size
While iPhones and iPads take HD quality photos, internal laptop webcams are a pretty solid way to go. While HD is great, the internal webcam on your laptop takes quality video at a much lower file size, which makes it easier to upload and share.
Advantage #3 - Still portable
Nothing beats the portability of a tablet or smartphone, but it wasn't too long ago we were all amazed by the portability of a laptop. You can still move your laptop around your classroom and put in a place to capture the action you are looking for. Even more - A laptop is much more stable.