It is important to caramelize the pastry: for flavour, of courxe, but mostly because the caramel forms a sealing layer which protects the pastry from the moist filling (usually cream) and keeps it crisp longer.
If you prefer not to caramelize the pastry, you can glaze
it with egg to make it look more attractive.
Making a successful feuilletage is not easy, especially at first. It is worth remembering that the great French chef Joël Robuchon, when asked: "When was the first time you felt like a real cook?", replied: "The day I made my first successful strawberry millefeuille". So, be brave and have a go!