To be fair, a good share (I'd say most ? But data is needed ^^) of advertising is designed to make you prefer a brand over an other once you decided you want a new product. I'm not sure there's really a lot designed to make you do a buy decision without a preexisting want (<--- I'm trying to avoid the word need here, because it's definitely not a need, but my english isn't good enough)

You argument still holds that advertising still makes you possibily spend more for the exact same thing, but it's hardly comparable to gambling addictive behaviours in my opinion.