Segments using props versus eVars on Ecommerce site

I have a situation that I need confirmation. I work on an ecommerce site that has  pop-up on the hone page for first time customers to register to get money off their first order. We track if the visitor clicks a button to register for the offer or not to accept the offer. 

- We use  a prop to capture if the visitor clicked the "register" button or the "no thanks" button"

- I created visits segments for the visitors who click "register" and the visitors who click "no thanks"

I apply the segment to see how many visitors completed a purchase who clicked "register" and visitors who completed a purchase who clicked "no-thanks"

I think my data is not reporting all of the visitors clicked "register". The orders and revenue seem very low.

I think a better solution would be to capture the data using eVar and creating a visit segment because the eVar is persistent.

I want confirmation that makes sens or is there a better way to create prop visit segments for order and revenue data?

Thank you