Greetings. First, there are no stupid questions... only stupid people who ask questions.
And this is a question that should be asked. Many folks think latex paints are paints with latex in them, which isn't the case. No "latex" paints have any natural latex, just synthetic polymers (vinyl) that act the same way natural latex does. I believe these paints are referred to as "emulsion" paints in the UK.
Basically, there are three types of paints that we use: Latex, Acrylic, and Oil-Based. Latex and Acrylic are water-soluble and Oil-Based paints require the use of paint thinner, turpentine, or other chemicals. The reason you see "latex" paints called for in prop plans is they do not react negatively with most surfaces. You can use latex (and acrylics) on wood, paper, plastic, rubber, real latex, glass, and just about anything and it will dry and look good. Oil-based paints have solvents in them that can react negatively with vinyls, rubbers, and some plastics, resulting in them feeling sticky for months or longer. There is also the benefit of being able to clean up or thin acrylic/latex paint using plain water instead of paint thinner. The only real downside is if you need a finish that is super glossy. Oil-Based paints offer much more gloss than latex or acrylics.
As for latex and acrylics, the vinyl polymers are much cheaper than acrylics, so "latex" paint tends to be about 20% acrylics and 80% or so vinyl, which is why buying a gallon of house paint is much cheaper than buying a gallon of acrylic paint. Latex paints are usually the way to go if you have a lot of area to cover and you're looking for a flat or semi-gloss finish.