A web-based platform is software operated entirely in a browser, with nothing installed on the machine you manage from. For a screen or video network that matters more than it sounds: the people who need to publish are rarely at the same desk, on the same operating system, or inside the same network.
It removes a whole category of friction. A regional manager approves content from a phone, an agency uploads without a VPN, and nobody is blocked because IT has not approved a desktop client. Updates land for everyone at once, so there is no version drift across a team.
The caveat is that "web-based" says nothing about where the work happens. Some platforms render and process in the browser and fall over on a modest laptop with a large video; others do the heavy lifting server-side and stay responsive on anything. It also says nothing about offline behaviour: a browser-managed network still needs players that keep running when the connection does not.
Worth separating from cloud-hosted, which the two are routinely conflated with. Web-based describes how you operate it; cloud describes where it runs. Software can be either without being the other.