Girls, is it worth buying a thermo mat?

Girls, is it worth buying a thermo mat? We have laminate at home. We laid two long mats and then covered them with a blanket. And we play on it. Since 3 months old. The minus is that when we're without diapers, we sit on these same mats (we do top cleaning with a cloth and everything). We tried putting cellophane under the blanket, everything slides and the baby grabs this rustling cellophane. Here's my curiosity: how long can we play with this thermo mat? Do we need to buy it? We haven't crawled yet. But we try.