Jessica Taylor wrote:

WAAS is insufficient for a precision GPS approach.

Nonsense. A fully deployed WAAS can provide precision GPS appoaches with
performance comparable to ILS (Cat 1).

GPS precision approaches use "LAAS",

Not necessarily. In addition to WAAS, JPALS may be used in the future.

which is basically the same as WAAS except that the differential
station is much closer to the airport

LAAS transmits signals on the UHF band. WAAS does not. LAAS can eventually
provide more accuracy.

OK, who is this Jessica dudette? Seems to be uncannily knowledgeable.

It may depend on the meaning of "precision." If you assume any
approach with vertical guidance then WAAS does. If you mean CAT I or
better that depends on where WAAS is/gets to performance wise. It was
supposed to provide CAT I but has had problems.

I have not kept up to date on LAAS but last I heard it may or may not
be developed.

Ron Lee