Why Canada GC is the Backup?

I am H1 holder, I know that USA GC might take long long time, so i decide to switch to Canada GC.

Here comes the question.

If i still need H1 sponsor to get a job after i got Canada GC, then why it is called the "Backup"? What kind of "Backup" it is offering?

I took it for granted that i will get sort of "Freedom" after i got Canada GC.

Your clarification will be greatly appreciated!!!


Thanks in advance