My guess is the sod was being worn down by people taking selfies and standing around waiting for others to do the same.
The club owners probably decided to add the stonework , so the people won’t wear out the grass any more...............
What people need to understand is that St. Andrews is a functioning public golf course. It undoubtedly gets a lot of wear and tear during the year.
That’s my guess also, although I prefer that they simply beat the selfie people to death.