As a general rule, most products will contain both. Silicones and Siloxanes are often used a because they 'fill in' and hide light scratches... some products, especially trade products designed for dealership showroom cars are packed full of them for just this reason. But There are may other reasons for putting them in products. I believe that they are even in polishes and compounds because they act as a lubricant during high speed buffing.
Acrylic polymers are used because they bond together very nicely (much better than natural waxes) and are very strong, although not quite as strong as P.T.F.E. derived products. It's all down to the way the chains of atoms bond together... if anybody here took chemistry, please step in now, because this is where I get of my depth!