Ideally, you should never need to look at your slides while giving a talk. Every time you turn away from your audience, you lose a little of their attention.
I appreciate it when a slide is a visual piece with limited text, and the notes are roughly true to the spoken portion (for when slides are distributed after a talk).
You can (and should) repeat key points, but every time you read, you lose your audience. And yes, you can have a little bit of text -- but since most people go too far in the other direction, it's best to aim to eliminate text entirely.
Slides should be simple graphical content to provide signposts and communicate things that otherwise cannot be expressed vocally.
I am happy to provide copies of my slides, but no, I am under no obligation to make them useful without me presenting them. They're my tools, not your reference.
IMO, this expectation has been driven by bad presenters leading people to believe they can get the same content without bothering to show up to the talk. Maybe that's true, but if it is, you should wonder why you're giving the talk at all.
I can understand marketing talks where all you need is you and your words, accompanied with some useless images.
It would be an utter waste of time if a tech talk turned up like that.
You may not like "marketing", but you're giving a talk to sell a vision. Always. Once you win people over, they'll seek out the details for themselves.
You still use the same rhetorical devices and ethos pathos and logos.
