Keep in mind Dish will only warranty either Dish branded parts or approved parts. While some Holland splitters are approved parts that Dish stands behind, I don't know if Dish will stand behind them being used for Joeys. Considering that Dish uses a lot of Holland splitters for all previous generation installs requiring splitters, the fact that they now have specific Dish branded splitters for Hopper installs suggests that they may be at least a little different from the approved red or blue Holland splitters, and I have found no literature that recommends using these Dish branded Joey splitters for other splitter uses, makes me think Dish prefers the Joey splitters for Hopper installs. They may, in fact, either preform better or have more bandwidth for future use or future proofing.
This may be something like when Dish required all installs to be with coax up to 2.2GHz, even though they weren't using the upper bandwidth, until LATER when Dish Pro was rolled out YEARS later. Dish often has good reason for it requirements that aren't always apparent to the rest of us.