If you have the iPad app
You continue to view the videos on your iPad. There is absolutely no reason to get the web version, as you already have everything in it. If you would like to view the videos on your computer you can do so with this software, which is free to try, $15 USD to buy.
If you DO NOT have the iPad app
You can purchase access to the web app using either link above. This allows you to view the videos on any device that can access the web. Those same links above will allow you to view the videos on a computer, a phone with Internet access, or a tablet. When viewing the site on an iPhone or iPad you will see a small icon at the bottom of the Safari browser screen. It's a square with an arrow pointing up. Tap that and you'll find an option to "Add to Home Screen". Choosing that will put an icon on your home screen that will allow you to easily go back to the web page.
In Summary: With regard to the apps on iPad and Apple TV, nothing has changed. If you have the app on one of those devices you are all set. DO NOT purchase the web version, as you already have everything in it in one convenient app. If you have been unable to use the iPad apps because your don't have an iPad or Apple TV you can use the web apps. They will work on anything that has the ability to view a website.