The millions of people that used to watch MTV's TRL to get 10 seconds of their favorite music video would disagree.

But I did watch it. I can't tell if it's a boon or bust cause I never heard the song, as you say in isolation. 

Exactly. If you read lyrics it has the exact same effect. Often have I listened to a song, read the lyrics and what I thought I heard was a disaster in reality. 

I do remember these times, good point. Not sure I would have liked half the songs on Sky music channels either without the eye candy. Damn, when I think about it on this perspective perhaps music videos held some value back then. 

Indeed, I remember flicking through music channels as I said above. Perhaps I am wrong, at least for a specific time period. I have to rethink my OP. 

If it makes music better for ya, nice one. I would recommend closing your eyes with headphones in or doing an activity and let the music make your own imagination go wild. At least try it. 

Indeed. It is and I will from now on. 

im going to give two examples just off the top of my head of how this goes both ways

example 1: good: soundgarden - black hole sun.
i would say the video definitely adds to the music. its weird and definitely not what i would be thinking when i heard the song, but in a good way. now when i listen, i feel like the song hits better than it did before now that i have seen the video. my daughter likes it when the barbie burns.

example 2: bad: linkin park - what i've done.
when you listen to this song, it sounds very introspective. it sounds like there is something somebody personally regrets in their lives and is in turmoil over it. that they have become something they dont respect and are having a hard time dealing with it. i think we can all relate to that on some level, either big or small. when you watch the video, its a bunch of war imagery. wtf? now for me, it doesnt "ruin" the song, but i do think it was a very curious decision and doesn't fit with the music. at all.

in the grand scheme of things, i feel like the video has no impact on the music. in these two cases i laid out, i think it does, but i do not think it is very common. 

Yeah. War imagery is so clitche as with the video added above and When September ends which I already mentioned, I can name so many but From Yesterday by 30 seconds to Mars and the Samurai video make no sense to the song and what's written and then they had a song called This is War and it's modern warfare but STILL, It doesn't fit the song despite it being about war. 

@OP. Idk why visualizer art didn't become mainstream before music videos. The only good music videos are that of 90's ballads, they made them epic and of high quality Hollywood production. If you're gonna do it, do it well. 

I don't think they're the worst thing, but I agree that they don't generally do anything of value. Much of the time, they feel like they're there just to grab attention. It's also not rare for music videos to not even match the song all that well - I mean they technically match the lyrics, but it might still feel very off, and that's probably because music video production can probably be very detached from actually writing the song. For these reasons, I don't watch a lot of music videos. I'm sure there's some genuinely good music videos as well, but I'm not too interested in trying to find them.

That said, lyric videos are something I have more appreciation of. Obviously they're not all great either, but they tend to feel less pretentious, and it feels like they can do cooler stuff visually without taking away from the music.