Yes - as long as you don't exceed the monthly 200GBP ATM withdrawal limit - your Revolut card is Free !
You can use Revolut for any number of transactions - online and offline. No charges.
There are fees for Premium Metal cards and other concierge services only if you choose to avail them - most users find the free services quite sufficient and phenomenally better than their own traditional bank !
I personally use Revolut as my primary card and absolutely love it as I can get all the analytics on my expenses, I can set a budget and change forex at the tap of a fingertip !
Best thing is - I don't pay for it and the app is super easy to use.
Everything you need to know about Revolut: The Ultimate Revolut Guide