Because there is a big standoff between Israel and Iran in the Middle-East. And minor, and especially tiny countries, seemingly are being forced to align with one of these countries.
All US-backed gulf states are moving towards Israel's side, mostly because of the Israel-U.S. alliance. The only exception (or, maybe looking like exception) is Turkey; it is trying to become a third regional leader in the Middle-East not aligned with the U.S.
Maybe, only maybe!, it is a probe by the Saudis; they may test Arabian-world reaction on such diplomatic act before establishing relations themselves.