Though they won every fight, The Mongols were taking higher then normal casualties when they attacked Central Europe. And since their fighters were trained from close to birth, they could not afford those high casualties.
Actually, they didn’t. They used two tumans under Buri and Kadaan to destroy one Polish Army in front of Crackow, sack Crackow, annihilate [almost to a man], a second army of 40,000 at Liegnitz, and to burn down Bohemia and Moravia. And that was just a feint.
Somewhere between 40,000 and 60,000 Mongols under Batu Quan and Subudei fought something like 100,000 Hungarians, and killed 70,000 of them at Mohi. They took Buda and Pest around Christmas, and by Spring they were raiding Vienna, infiltrating northern Italy, and had a tuman chasing Bela IV down the Adriatic coast. They couldn’t have done that with higher than normal casualties.