Scripts vs Smartforms vs Interactive forms

Hi experts,

Answers to the following questions as well as any relevant links will be appreciated:

<b>What is the necessity for customers to get converted to smartforms from sapscripts??

What is the process to get along with this conversion??

Are all standard sapscripts have related standard smartforms available in the system?? How to find them??

What is the effect of interactive forms over sapscripts/smartforms in future??</b>

The above questions are based for version ECC 6.0

Advance Thanks