What is the Bloom filter for in Bitcoin/Ethereum?

Question

bitcoin

As I understand it, the Bloom filter is used to search for interesting transactions by a thin client. And why should the client look for this or that transaction? In addition to searching, is the filter used for anything else? And the bloom filter provides anonymity, anonymity of what?

Answer 1

https://ru.wikipedia.org/wiki/%D0%A4%D0%B8%D0%BB%D...
In a word, using the Bloom filter, you can assert with some probability that a transaction is available or not. Nothing more can be done with it. But it has a very useful property - it takes up much less space (and searches for the answer to the question above faster) than a complete index of all transactions included in bitcoin.

Answer 2

And why should the client look for this or that transaction?

I must say right away that I did not look at specific implementations, I need to check. But logically, it will look for transactions associated with its keys. Otherwise, how will he understand that a payment has arrived while he was offline, for example?
And to send funds, you need to know the transactions whose outputs can be spent. And the thin client does not store full base.