When you neither have a lifetime pack purchased once nor have an active subscription, you may still be allowed to use certain features of the app to get an experience of the app. However, in such a situation, we display advertisements from a few sponsors - that support new feature additions, and improvements of the app.
If you do not want to see any advertisement, you can purchase a lifetime pack or subscribe to a preferred plan. Not just that, once you have an active subscribed plan or lifetime pack purchased, you will have no limit on using brushes and styles available through the left panel on drawing canvas.