Do you still need ALA Omega 3 if you take fish or algae Omega 3?

I cant find any information about this honestly. Everywhere I look it says ALA omega 3 is an essential fatty acid. And the body can in theory make EPA & DHA from ALA. So from that point of view, taking only fish oil wouldn't be enough, because it doesn't contain ALA but EPA & DHA omega 3. Does the body need ALA for anything else? Or do these articles mean, you need ALA because the body makes EPA & DHA out of it. Do you need all three, ALA, EPA & DHA?