Targeted is a relative term.

It may be very targeted compared to traditional television and radio advertising.

Yet it could still be less targeted than ideal.

Let's say my ad was profitable via traditional radio and television advertising.

If only 1% of viewers were in my target audience for traditional television and radio advertising, and Roku can get that number to 2%, they've just doubled my roi.

Targeted doesn't mean perfect, it just means better.

Talk to someone who heavily uses Instagram. I guarantee the ads there have gotten them to buy something. I never succumbed to ads until using IG in the last few years.