Tried these once on a customers Guitar.
The old girl had seen some use so a fret level was needed.
Installed nut then selected the correct fret wire etc.
Then the fun began. Due to the fret dress the zero fret needed some work to get it spot on across its length. Also the built in radius on the nut wasnt quite right..
This is not easy to do and get right once the fret is glued in. LOTS of swearing and pfaffing arond with jewelers files and wet and dry...

On newer Guitars, this shouldn't be an issue provided the frets are level etc.

End result, happy customer. He got the extra twang he was after.
Happy Luthier? Not so much. A lot of fiddling around on a job that should have taken an hour tops...