Why buy a ground lease...price of land seems unusually high compared to total of project?

the total of the project is irrelevant. how does it compare to the price of land for new developments of the same type. then there are other factors to consider as well, but mainly the above and the rate of return. University of Texas did a great paper on ground leases that gives many reasons why one may consider a ground lease.

Another consideration for buying a ground lease is your long term investment planning. If you are looking for an asset to pass along to your heirs a ground lease is a great way to build valve during the term of the lease and be able to recapture not only the land but also the improvements at the end of the lease. With that in mind, make sure the lease document includes strong language requiring the lessee to maintain the property.