I'm glad to hear someone else come to this as the solution for ads.

Wait, what? I'm confused. Is the entire product catalogue considered an ad? Or do you mean parts of a product catalogue can contain adverts? I'd argue a product catalogue is not advertising at all.

Anderton's (a music retailer in the UK) has an enormously popular YouTube channel (1M subs) which is basically just them demoing their stock while shooting the breeze. It's 100% an advertisement, but it's the sort that most people (including myself, who otherwise hates ads) is fine with because you have to seek it out.

This is the type of advertising I actually like.

I'm a huge buff for music gear/tech. I love seeing the newest plugins, pedals, software. I actively seek it out. I know demos of products are effectively advertisements, but they are the right type of ads and aimed at a crowd that seeks info the right way and likely is a higher probability of making a purchase.

I consider each product listing in a catalogues to be ads, or perhaps the whole catalogues is one big aggregate ad. Either way, I'm fine with them. Product catalogues are mostly innocuous and usually provide more empirical product information than other forms of advertisement.

Cool, I'm fine with them too. As long as they're not mailed out without consent.

Of course it's advertising. It's telling you about products you can buy, pushed by people who want you to buy those products, and they can pay money to be on an earlier page (we should probably ban that). But the general idea of a product catalogue shouldn't be illegal even if ads are illegal, because it's actually useful and non-invasive.