The important thing here is that it's a tradeoff, not an universal good. And a tradeoff that I personally don't like very much. Doing fun and interesting things keeps getting harder and harder because you have to jump through increasing amount of security hoops. For instance, reading and writing memory of other programs enabled you to do tweaks that are now almost impossible to perform.

I understand the need for change, now that a computer is expected to be connected and running untrusted third-party code by default. But we've lost something with that change, and I wish for a way to get it back.