I'm guessing that comes down to the medium used to grow it, which is often fetal bovine serum, making it non-vegan.

Whether or not it’s vegan is largely unimportant.

There are three main reasons people go vegan - environment, ethical, and health.

Is lab grown meat better for the environment? Absolutely. It takes less space and removes parasitic losses such as movement, body heat etc. It can’t ever be as efficient as eating plants, but it will be orders of magnitude better than animal ag.

Is lab grown meat ethical? Well, it reduces animal suffering to near zero. That’s pretty good in my opinion. But opinions will differ.

Is lab grown meat healthier? Maybe. We should be able to grow higher quality cuts with fewer steroids and antibiotics. But red meat is still carcinogenic. So if someone gave up meat for health, it seems unlikely they’d eat lab grown meat.