What are the gold bars for and where are the ones I earned from the team challenge?

Gold bars are used exclusively to select styles for certain 3x3 buildings and the 4x4 Estate. If you tap on these buildings and select the green button with the house and hammer icon, it will take you to the Style Picker, where your amount of gold bars are also displayed. At this time, the buildings with Style Picker options are only: Estate, Fountain, Stables, Orangerie, Windmill, Vineyard, Central Station, Observatory, and Bathhouse. But more are anticipated.

So my bars are useless right now waiting for more buildings to be released? I have tons of gold bars and don’t know how to use them. And the best answer from this group is more buildings to be released. I have all buildings and at the highest receiving flowers. I wish I could spend my gold bars on other things in the shop?.