Thank you for reaching out and sharing this feedback!
The banner at the bottom only appears while you're still on trial, as a reminder of how many trial days are left. Once you've selected a plan and the remainder of the trial duration has finished, the banner will disappear from the admin.
That being said, did you get a chance to look over our monthly plans and decide on a suitable one to move forward with your store?
So Im in the process of becoming a Shopify Developer and just training atm. Getting used to the site so I'll be able to do it for clients. I guess when Im working on actual shopify stores with plans I won't have to worry about this.