Isn't plant-based omega-3 just flaxseed that doesn't convert?Updated 2 hours ago

No, and this is an important distinction. Flax, chia, and walnuts contain ALA, a plant omega-3 your body has to convert into EPA and DHA. That conversion is very inefficient (often only a few percent), so ALA sources leave many people short. Better Omega-3 skips that problem entirely: it gives you preformed EPA and DHA (the same ready-to-use forms found in fish oil)  grown from algae. This isn't flax.