...But I noticed that the Binnace Smart Chain has been under severe attacks recently. Is it because of low number of validators leading faster transactions or what?
It's not the BSC network that's under attack but the platforms built on top of it. Do not mix them up. Put the blame to the project developers who made the codes that were exploited by the attackers.
It's the same thing when platforms on ethereum chain are exploited. You don't put the blame to the miners and the thousands of nodes running the network.