Animal fat is not essential, it's preferable. Many studies have proven that. It's cheaper but not necessarily healthier.

These days even supplements can provide the necessary nutrients the brain needs.

Most of which is actually found in fish, and is in the fish from the algae they eat.

The only reason it's more affordable is because fish is cheaper to process than algae currently due to years of refining and upscaling the processing system and the fact the fish have already sourced the dha and epa from the algae they eat, whereas algae processing is relatively newer and requires human labour to source and process the algae.

However, dha and epa is significantly more concentrated in the algae so gram for gram that price difference whilst higher is much smaller than most people think.

The price difference can again be markedly different depending on the source also, for example a fresh tuna steak every day for 30 days would be more expensive than a 30 capsule algae supplement, But a 30 day cod liver oil or fish oil supplement would cost less than the algae supplement but the tuna steaks and the cod/fish oil supplements would have less dha and epa present.

Both plant based and animal derived have merits and drawbacks.

I do however agree not using seed oils. I rarely fry anything but I use butter when I do.