Why is the "Premier" version recommended for investment filers?

I see the Premier version is recommended for tax filers with investment transactions. What does it provide that the Deluxe version does not?

 

I had stock and mutual fund transactions last year using Deluxe and had no issues. I used the Desktop version. This year I will have a RMD from a IRA.

 

The compare versions of TurboTax webpage says "Additional Help" is available under the Premier version. What exactly does this mean?

 

Thank you.