I guess that's it .... I can fully understand, and agree, if there's some type of age verification pop-up when one goes to purchase items. And the results can & should be recorded into the seller's database/ecom system. And I'm sure there's many localities where selling vape gear to minors is forbidden, so its more than CYA.
But having age pop-ups just to view their site ... without a purchase ... is silly. Further, I've seen some really crappy web programming - having an age pop-up on every page. Or when browsing from a cell/tablet, the pop-up is off the view port where you have to scroll over, if even possible. And as a developer, know there's absolutely no way to ensure that the person who said they were 100 years old when entering the site is the same person buying the vape gear - especially on a public computer. The CYA the website owner thinks they're doing is not covering anything, just forcing extra user clicks from every visitor.
You're right, in the scheme of life, its trivial. But as a developer, I think its asinine, and terrible coding & design.