Why might a Thinkpad'e P50/70 need ECC RAM?

Question

Iron

I noticed that this laptop model is equipped with a very good Xeon processor compatible with this type of RAM memory. As I found out, the latter is characterized by increased stability and is used mainly on equipment that must work continuously without failures. The questions are as follows:

• why exactly (subjectively) is it advisable to take exactly ECC memory and how much is it inferior to conventional?
  
• Is it worth paying so much for it?
  
• Does memory type have a significant effect on virtualized OS performance, and if so, what should you pay attention to?