As other commenters have pointed out, this is backwards. The unsolvability of the halting problem says that there is no one algorithm that can tell you whether

As other commenters have pointed out, this is backwards. The unsolvability of the halting problem says that there is no one algorithm that can tell you whether an arbitrary Turing machine will halt. But for special types of Turing machines, it is often possible to say whether they will halt. So, if you define a special type of Turing machine, and it turns out that the halting problem is unsolveable even for that restricted type, that is noteworthy.