In short: T-Mobile's Layer3 TV service is reportedly now being offered in select markets with additional discounts available to existing T-Mobile customers. However, this does not currently seem to be a proper rolling out of the new service, but more so a testing of various price points in different locations, ahead of a full and proper launch.
Background: T-Mobile acquired Layer3 back in December 2017 with the suggestion the service would go live at some point in 2018. It had been highly expected the revised TV service would be properly announced during the last Un-carrier announcement although that was not the case. While it's still expected the service will fully launch in 2018, it seems T-Mobile is already selling Layer3 as a product although not quite in the way it's expected to later in the year. For example, the current reporting highlights T-Mobile representatives selling the traditional Layer3 TV service to existing T-Mobile customers at around $80 per month – a discount (which in some cases amounts to $40 per month) compared to what the service is sold to general customers at. In contrast, it's expected the new TV service will launch as more of a digital-first offering (unlike the package currently being sold) and there has even been the suggestion it may arrive to market as an exclusive product. Meaning it will only be available to T-Mobile's existing mobile customers.
The impact: The news here suggests T-Mobile is trying to determine the ways in which it can capitalize on a Layer3-based TV solution in the future. While the current understanding is the new version will arrive to market as a wireless-based service it could be the case T-Mobile also plans to launch a more traditional interpretation of the service in the short-term. Possible, to either generate additional revenue, or to cater to those who have still yet to transition to more of a cable-free TV lifestyle. Considering the wireless nature of the new T-Mobile TV service is expected to be one of its key and main selling points, offering those customers a TV product they are already familiar with may prove enough to help those same customers transition to the newer product when it goes live. Especially if they are already of the understanding they are gaining access to the service at a reduced cost simply by virtue of their T-Mobile mobile plan.