Hi,
No need to say sorry, I don't work for VMware, just trying to summarize the reasons for you.
If you don't use the internet on your development machine I might agree, otherwise I think the security arguments still count, but that's my opinion on the matter.
Of course it is up to you to assess the security landscape and deem something important or not.
PS: re. but it works, yes there are reports that an existing install of Fusion 8 on macOS that was upgraded to High Sierra can work, but installing fresh will be problematic due to apple's new kernel signing requirements. Not supported just means that.. all problems you bump into are yours, only support that can be offered in that scenario is via this forum.
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Wil