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Re SI and nothing else

On Oct 16 1997 James Wheeler wrote:

1 m = (1/3x10^8) s
1 m = 10^15/(197.3 MeV)=10^28/(1.6*197.3 J)
1 m = (9/6.67)x10^27 kg
(if I've done the math right!)

Ludwik responded:

The units do not balance. What does it mean "an equivalence between
A and B"?

James replied:

Take the case of the speed of light. 1 second is equal to 3x10^8 meters,
or one second is equivalent to 3x10^8 meters.

I think it is better not to use the = sign for "A and B are equivalent".
We can use =>, for example. Why? Because A=B in physics usually means that
A and B are identical, both numerically and dimensionally.