There are more courses like this other than Harbour Town actually. Hope they'll be all available for stroke play "soon"*. (* I know it's a very relative term for WGT. LOL)
I have learned over time that "soon" is an acronym for the Twelfth of Never on the WGT calendar.
Alas, this is another case.
Remember that WGT courses are based on real photographs. That said, on those "CTTH only" courses, they shot less photos, just what they needed. Therefore, an upgrade to "full course" would require a new visit for (my estimate) a new full set of pictures and contures, implying negotiations and contracts and a lot of work and costs!
Also, as the Bandon Dunes example shows (*), many courses aren't suitable for WGT as they lack the course length for all the deChambeaus in this game. Those "parking lot" tees must exist to be photographed!
(*) One course at Bandon Dunes Resort comes close to 7,000 yds (6,944), three others are between 6,600 and 6,800 yds, probably no match for our virtual clubs!