Definitely is what I say!
Why you ask?
1. Makes lipstick last longer by giving the lip colour something to anchor to
2. Leads to fuller looking lips
3. Creates the perfect cupid bow by letting you define a great lip shape
4. Prevents bold lipsticks from running or bleeding around your mouth
5.Makes the lipstick colour look richer and more intense.
Even though lip liners have so many uses, it doesn't mean you have to buy a whole bunch of colours to match each and every shade. your safest bet would be one shade darker than your natural lip colour, or it could be a neutral, natural lip liner with creamy consistency
What is the one lip liner I swear by?
According to me that lip liner is SOAR by M.A.C. This colour compliments the nudes as well as the bold colours like red or bright pink. The other reason I love SOAR is because everytime I have bought a bold shade (could even be a pink or coral) that looks insanely stark on my skin, I use it as a base to help reduce that stark difference but keep the vibrant colour.
Check out the swatches below where I've used SOAR as a lip liner in all of them.
Filled my lips with soar lip liner
Filled my lips with Soar lip liner and Liquid lipstick in Doting by The Balm Cosmetics.
Outlined and filled my lips with Soar Lip liner and Ruby Woo lipstick by Mac cosmetics.