"Is Zoho CRM customer" vs "Is linked with Zoho CRM"

"Is Zoho CRM customer" vs "Is linked with Zoho CRM"

Recently while building a Flow, I was setting up a Decision action following a Zoho Invoice Fetch record action. There were 2 choices that I had not seen as something I could manually action in Zoho Invoice:
"Is Zoho CRM customer" and "Is linked with Zoho CRM".

Are these criteria that Zoho Invoice tracks/designates when Zoho Invoice and Zoho CRM integration is turned on and what is the difference between them?

Is it as obvious as it appears?