True for EB.I don't see how this invocation can be read to do either of those things. For starters, eldritch blast does not have a material component, so the weapon does not serve as an arcane focus for that spell anyway.
But there other attack spells that can use it as an arcane focus. Like witchbolt.
That's the part in question.2) your weapon gets +1 to its attack and damage rolls
You are making a (spell) attack roll, with the weapon (as the focus).