Why does the USA gives so much money to Israel every year and gives them weapons? What benefit does Israel give the USA?

Partly convenient geopolitical ally (the borders were carved of the region not long after WW2 with the enforcement of the Allied forces) and partly Dominionism where a certain subsection of Christianity, predominantly Evangelicals who are very politically motivated, believe that when Israel controls Jerusalem, the holy land, that is one of the portents of the predictions made in the Book of Revalations, ushering in God's kingdom on earth and the end of time.

Yep. USA pays money to support Israel in hopes of triggering Armageddon. Your tax dollars at work.
- The funny thing is they think the anti-Christ will unify “the holy land” and they’re still for it.

Israel (and KSA) serves to destabilise the West Asia, region which is crucial both economically and strategically to petrodollar and to military part of US hegemony. It also served and still serves as proxy war area against USSR and now Russia.

Absolutely worst scenario imaginable for USA would be that area unifying under some kind of Arab entity.

My PolySci professor explained Israel as America's retarded cousin. He said America gives the idiot a stick and says "I don't like that guy". The idiot runs over and hits the other guy with a stick. America says "it wasn't me, it was that idiot." and when his retarded cousin comes back, America gives him a bigger stick.

In addition to the below, Israel also shares intelligence with the CIA

In a lot of ways Israel is the testing grounds for new weapons and tactics. Once tried, tested, and perfected, they are brought back to the core.

And I am guessing that Palestinians are the test subjects?
- Indeed they are. Test the means of oppression abroad, bring it back home once the bugs have been worked out.
- Not really, the American government doesn't really care much about Palestine.
  
  The west allies with Israel and Saudi Arabia as a way to keep Iran from overtaking the entire area.
During the Ferguson uprising after Michael Brown was murdered, Palestinians on Twitter recognized the weapons police were using on protestors, like matching teargas canisters.
- I also remember seeing an Intercept article talking about new generation of Homeland Security Mexico border surveillance tech being tested on Gaza and the West Bank first.

Israel is simply another branch of the US military.

Empire!

These takes are all wildly all over the place. The truth is Israel provides a stable partner for the region with ideals much aligned with western interests than the surrounding neighbors in the region.

Gives the christian nationalists the ability to tell Jews to go to Israel cuz the us is only for wasps.

I've actually seen this in real life.

Israel is a vassal of the USA. It allows the US to have a military presence there, on the door of the middle east where it can challenge its enemies and see about oil politics.

The biggest perk is the control of the eastern Mediterranean Sea with its fleet. This is to fight Russian's fleet there.

The same goes with Taiwan and China. USA cares for Tawai because it's a strategic lock for China's fleet.