I met up with my cousin today and he told me that I shouldn't vape anything other than nickel in temp mode.
First... that ignores the existence of Titanium, Stainless Steel, Kanthal 52, etc. for TC use.
To your question, yes it's safe but most TC mods will kick out of TC Mode when they don't see the expected rise in resistance. Others allow it, but there's no TC function or dry hit prevention happening.
And the IPV D2 needs it for high ohm/low power coils because it cannot "step down" below the battery voltage in power mode.
I haven't looked more into this, but I believe in Power Mode, for "hotter vape" users, we run a tad higher than the standard max temp of TC mods (~600F).
So yes... KanthalA1 would be safe in TC as well, though of course the TC isn't limiting it.