Just to make it clear, the wines by the glass on the regular and upgraded drinks packages on O include ALL the wines by the glass available onboard. In other words, regardless of whether guests choose a drinks package or pay for drinks as they go, all will be choosing from the same list of wines by the glass. Although the selection may vary from cruise to cruise, you can get an idea of the wines by the glass here: https://www.oceaniacruises.com/Documents/Menus/1694/Bar-Menu.pdf.
I much preferred the way O do it to Viking, where we had the upgraded package but found it difficult and slow at lunch and dinner to order wine that wasn't the included wine of the day.