That's a common use of NFTs--esp. Polygon ones, but even ETH ones lately with gas being low. No offense, but I'm not a big fan of that practice (airdropping promos). I personally find that such NFTs clog up my wallet, and I wind up hiding them--and pretty much always consider them suspicious. The only time I'd ever airdrop would be if I were doing so on behalf of a team who are airdropping to holders of their NFTs -- and such airdrops would therefore be welcome by the recipient. A lot of high-end influencers particularly dislike promo airdrops. People typically drop things into their wallet to make it falsely look like the influencers bought into their projects. So, again, not something I would personally recommend.