401 - Oil & water temperature gauges

[p5b401]

Not having had driving/operational experience, I'm not sure if the temp gauges are working correctly. The oil temp hardly moves and the water temp is so slow the thermo fan can cut in an out several times before the gauge registers somewhere near correct.
Pipes to both gauges have had some obvious kinks in them which previous owners/mechanics have 'sort of' straightened.

I'm wondering if there is a practical need for the oil temp gauge or is it just a flow on from its aircraft heritage?

I'm thinking of removing the existing oil temp system and replace the water temp with an electrical style but with the same case and in the same facia style (minus any oil temp scale). Has this sort of thing been done before and does it detract from the vehicles heritage?