The heated roller has been standard in Roll Laminators for many years, This provides the advantage of avoiding the "silvering effect". Silvering effect means, that you have encapsulated air, so the glue is not connected to the print on tiny parts of your print material. When working with selfadhesive films, the heat will warm up the glue, so it will fill up the "rough" surface of paper or vinyl. The effect is, that you will have less air encapsulated and the result is more brilliant.
If you are mounting prints behind glass or plexiglass you would need to have a heated roller because the glue should be absolutely transparent. The heated roller would provide a perfect result.
Especially for Fotographers or for producer of glass-products, the heated roller is a recommended feature.