Evidence that Macros Do NOT Cause GCD Delay or Lost Casts

[Rein_eon_Osborne]

[...]I had never heard there were Balance theorycrafters who would be important to send this to. Tell me a way to respectfully get in touch with them and I'll be happy to.

Their #rules section have a minutiae that specifically encourages theorycrafting & "challenging the meta" from its members.

Go try your luck.