TL;DR: It gives me ideas of ways to spend money I was already going to spend, but now I have a place to start my research with some concrete ideas.
Well, I've given the example of live shows a couple of times. I've been to a few live shows that I learned about from targeted ads. Those were experiences I enjoyed and would not have learned about otherwise.
I'll pull up my Insta feed right now and list the targeted ads:
Osmo -- This is a game system for my kids that I already own. The ad isn't super useful, except I just learned about a new game they're releasing that I might want to get for my daughter. I may have eventually seen this elsewhere, but this is the first I'm seeing it.
Osmo again. But from a different vendor.
Lego -- They have some new sets that I didn't know about. I enjoy building legos with my kids, so now I know about a few new sets we might enjoy together.
Something called Soundbrenner. It's a gadget for musicians. I'm not a musician so this doesn't interest me. None the less, I am glad I know about this because I have musician friends who might be interested in something like this, so maybe the next time I talk to them I'll mention it, and they may be appreciative of me telling them because it can give them an idea of a new way to improve their play. Maybe they'll buy the gadget, maybe they'll find something similar, maybe they'll build something similar.
A charity for helping teachers during Christmas. This interests me. I support education and there is a good chance I'll make a donation to this cause. Now I'm happy that I found out about this charity.
An ad for a service that turns pictures of your pets into hand done oil paintings. I don't have pets, but one of my best friends does as do my parents, so there is a possibility I'll use this service as a Christmas gift.
A contest to win a Lamborghini featured in a lady gaga video. This is mistargeted and I have no interest.
A food sealing kitchen gadget. I'm going to forward this to my wife, who loves cooking gadgets, and then she'll check her cooking forums for someone who had a DIY version, but now she has a new idea to ask about.
Bed Bath and Beyond. Meh, don't really care.
A clothing company that follows the Tom's model of buy one give one. I don't like the clothes, but if I did, this is the kind of thing I might support if I need new clothes.
Some sort of prescription drug. The ad doesn't even say what it cures. So I have no interest in this. However, if it happened to be for an ailment that I actually have, I'd probably click through to find out more and be a jumping point for my own research.
Quicken Loans. I actually hate this ad because it encourages people to refinance their 30 year mortgage into a 15 year mortgage which is a terrible idea.
Another ad for musicians, this time an app. Same comment as above -- not interested but I may mention to a friend.
An ad for a new star wars game in VR. As it turns out, I recently bought an Occulus (from someone on HN actually) so this might be a game I would be interested in. I probably would have found out about this later when looking for new games, but this is the first I've heard of this game.
Another Lego ad, this time a different set.
Anyway, I could keep going, as the ads are endless (although they start to repeat). The point is, in most of these cases, I learned something new that I didn't know before.
Yes, in every case, they are trying to get me to spend money. But it's money I probably would have been spending anyway (Christmas presents, games my kids and I can play together, games I can play alone, charity donations). So I'm glad that I now have some ideas and places to start looking.
In a lot of cases, the ads are just jumping off points for research, but they give me new ideas I wouldn't have thought of.