Can the current European sanctions against Russia have a significant effect?

Many European countries and the EU itself have imposed economic sanctions on Russia over its invasion of Ukraine. However, according to this Guardian article citing this study, European nations are also still paying Russia almost three hundred million dollars a day to buy fossil fuels:

Vladimir Putin’s war in Ukraine is being bolstered by $285m (£217m) in oil payments made every day by European countries, new analysis by the Transport & Environment (T&E) thinktank has found.

What's the point of blocking some Russian banks from SWIFT or impounding the assets of people linked to the Russian government if, at the same time, the very same states are giving that same government hundreds of millions of dollars a day?

I have seen various claims that the sanctions are crippling Russia's economy, but how much difference does it really make if it is still also receiving these significant sums of money?