This was almost certainly done to punish Israel:
The United Nations General Assembly on Thursday overwhelmingly approved a resolution upgrading Palestine to a “non-member observer state,” from a “non-member observer entity.”
Before the vote and in front of the assembly, Palestinian President Mahmoud Abbas said this was the body’s “last chance to save the two-state solution.”
He said despite all the violence and Israeli “aggressions” and its “occupation,” Palestinians and the Palestinian Authority have insisted on harmony and have looked at the “U.N. as a beacon of hope.”
“We did not come here seeking to delegitimize a state established years ago, and that is Israel. Rather we came to affirm the legitimacy of a state that must now achieve its independence and that is Palestine,” Abbas said.
Pretty words. But Hamas, who control the Gaza, do not recognize Israel’s right to exist.
The main thing this does is give them access to the International Criminal Court. Does anyone want to be on how long it will before they deluge Israel with accusations of war crimes? About ten seconds? And does anyone doubt what the result of those investigations will be?