That's correct. Making money from Tapas is a perk exclusively for creators who have unlocked tipping and-or ad revenue. Even then, it isn't a significant amount of income compared to Patreon funding, Kickstarter campaigns, merchandise sales, and the like. Ink earned by watching ads is mostly useful to you for unlocking premium series, but you can tip with it also.
$0.0009 earned per drop of ink (based on the numbers that @tired_programmer just gave us) seems rather close to what I remember being mentioned was the going rate for coins a couple of years back, maybe slightly higher.