How important is 16gb VRAM in MSFS?

I’d not recommend anything under 16 GB. If you plan to fly to / from large, complex airports or fly complex airliners like those from inbuilds & PMG, or use DX12, 16GB will help lot. See the second paragraph in this post by @Tremaine111:

Other comments on the forums about having 16 GB include:

and

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