Technically, why does RDM's Vercure heal more than SMN's Physick?

[Raikai]

RDM's vercure scales off of INT while SMN's scales off of MND.

The devs will tell you SCH jank is why SMN physick scales off of MND but at this point its vestigial.

This is actually not true, both SMN and SCH physicks are different spell instances, as one can check in the Garlandtools website.

In fact, they purposedly created a SMN physick scaling with MND back in Stormblood while the previous one remained the SCH's one. I know that because I remember when I changed to SMN back then the Physick spell was greyed out (as in removed) and I had to drag it again from the spellbook to my hotbars.

The reason why Physick scales with MND seems to be an actual choice rather than a consequence of something.