Beading is function of contact angle product imparts on surface among other things.
Mineral seal oil is common active ingredient in many drying agents. It imparts angle of about 80 degrees. Beading effect is about same as water drops on human skin.
“….from what it says here, the product will dry, enhance gloss and smoothness.”
Sure, all drying agents dry and enhance gloss and smoothness comes from salts.
Silicone is an active ingredient in some tri-foam, clearcoat and imparts angle of about 90 degrees. So, beading effect is much greater than mineral seal oil also costs more.
Rain-x online, ICE, etc. imparts angle of about 100 degrees and beads up like crazy and costs more.
Difference in price per gallon is due to position in value chain.
$400 is most likely local or regional supplier shipping smaller quantities and volume versus KR which is national supplier that ships larger quantities, higher volume and lower prices.
Same dynamic exists between local hardware store and Home Depot.