In the US homeless people might sit on park benches and be seen so benches are sloped to be uncomfortable for more than short periods. Benches are intended as a temporary rest for those that need it as they walk, not a place to just sit and chill.

My area's solution is we don't have parks, we have public land trusts that are actually private property and can ban people. They're pretty nice for those of us allowed.

In the USA people would graffiti the benches pee on the seats and a homeless person would move in. Almost no protection exists to prevent destruction of public property. I think that’s intentional to discourage people from embracing socialism.