Power BI Embedded - Subscription Questions

I want to embed Power BI reports in my app that is used by our customers ( I want to use Power BI Embedded).

I am a little bit confused about the different subscription options available. I have 2 questions:

1- Can I buy a Power BI Embedded subscription (A1 to A6 SKUs) without having a Power BI Premium subscription (with just having a Power BI Pro license)?

2-  What is the difference between the EM SKUs subscriptions and the A SKUs subscriptions?  When should I use an EM subscription over a A subscription?  At first look, A subscriptions look more interesting since no yearly commitment is required.

I previously read the What is Power BI Premium and Power BI Embedded pages.