payment – Why would applications use Lightning over a channel TX?

I'm trying to understand the software-oriented payment usage cases for Lightning payments.

Since a web application was accepting BTC payments billed in Satoshi for a service – watch videos for example; why could it be advantageous to use LN to continuously generate new invoices (per second of display time), instead of just timing the overall billing and billing time? once at the end via a standard TX in chain?

The only advantage I see at atm is a coverage against the prices of the channels, by opening a channel of "long duration".