Title text:
'This HAZMAT container contains radioactive material with activity of one becquerel.' 'So, like, a single banana slice?'
Transcript:
[Cueball holds a stick while talking with Megan and White Hat.]
Cueball: This stick is one meter long.
Megan: Cool.
White Hat: That's a nice stick.[Cueball holds a smallish rock.]
Cueball: This rock weighs one pound.
Megan: I'd believe it.
White Hat: Looks like a normal rock.[Cueball holds a small battery.]
Cueball: This battery is one volt.
Megan: Seems fine.
White Hat: Might need a recharge.[Cueball holds a capacitor while Megan and White Hat panic.]
Cueball: This capacitor is one farad.
Megan: Aaaaa! Be careful!!
White Hat: Put it down!!
Source: https://xkcd.com/3106/
I would argue that a legally defined conversion to a meter or another metric value does not make a unit metric in and of itself. Those units have to adhere to the system, which is clearly based on decimal values, not just some arbitrary conversion with an absurd precision that was only signed into law to minimize the inconvenience caused by non-standard units.
It's not a defined conversion, it's the literal, internationally ratified definition of what those units are. Or maybe "redefinition" ought to be the word there; prior to that definition there were several very similar, roughly equal but ultimately not internationally standardised units in use. And since they were redefined in terms of SI units, they're technically SI.
This is one of those "tomatoes are technically fruit, but no-one with good sense would put them in a fruit salad" situations.