Many countries still don’t need a visa, you just fill out your itinerary ahead of time online and pay ~$20 USD equivalent fee(thanks to e0qdk for the conversion).
Instead of filling out a visit registration card after arrival, you fill out your visit registration ahead of time online.
Streamlines entry, boosts security.
There are still about 9 months for them to finalize policies before ETIAS registration becomes active, so we’ll have to see what the actual policy is once it’s enacted. Entry/exit policies change constantly, and this one hasn’t even begun yet.
It would be pretty ridiculous to pay for a layover.