Shopping carts have been proven to reduce the conversion rate (% of intent to buy which converts into an actual purchase) because those extra steps between "adding to cart" and paying give the brain a lot of time to think things over. There's a reason why Amazon pushed the one-click shopping. The less steps involved, the more you sell, impulse purchase is not a myth.
Is it possible it's reverse for some people? Because I realized I impulse bought a lot of multiple things at once. The last time I bought something seperate was Death Stranding in August and Beautiful Desolation in Feb. For Steam I can put stuffs into the cart, turn it off and do something else, then next day coming back and those stuffs are still in the cart. For Epic, I can click purchase something to check out the price after coupon discount, then turn it off, then I completely forget about what I was going to buy.
Meanwhile I'm here debating whether I should buy The Pathless for 6 dollars. Honestly I found a platform having a built-in wallet system makes it easier to impulse buy rather than... the lack of shopping cart.