The Mongols destroyed their competition and allowed Europe access to Asian goods.
Before the Mongols Central Asia was arguably the center of civilization and you had to go through them, the Uzbeks, Khwarazmians, Kyivans, Pashtuns, Cumaks, Iranians, etc if you wanted to trade with China which itself was disunified so even if you got to China you had 3-4 kingdoms you had to deal with.
Mongols came through, destroyed all these kingdoms and massacred millions of people, united China under one emperor and basically took out the middle men that was preventing western Europeans from getting a sizeable return on trade.
That’s why the Silk Road is looked as this great thing and world changing event by Europeans because they weren’t effected by it and were able to profit from it as they could now travel freely to China and beyond gaining wealth. The Mongols just liked to receive tribute and be told how great they were and they both hated Islam so it was a win win. Meanwhile in Islamic, Eastern European and Central Asian sources it’s an apocalyptic event that they still haven’t recovered from.
Look up cities like Samarkand, Baghdad, Merv, Bukhara, Garanj before the Mongol conquests. They make Rome look like a pastoral village.