I agree with Danielescarpetti regarding the interpretation in a musical sense.
Regarding the part: period instruments yes/no?
Limiting myself to my instrument, I would draw an imaginary line between the harpsichord and the fortepiano where there was a turning point in the construction of the two instruments.
in general terms, I believe that a piece written for harpsichord should be performed on a harpsichord, not necessarily a period one, but it must be a harpsichord, and the same applies to all other instruments; whereas for the fortepiano, there is the classic exception that proves the rule: Mozart.
I prefer his music on the piano, more brilliant, sonorous, and malleable than the fortepiano, but even here the difference between the two instruments is less than it is between the piano and the harpsichord.
For wind instruments, I would apply the same rule: today we would never play on natural horns, but we would use modern double horns which are higher performing, but they are still horns. Same thing for all other instruments like trumpets, trombones, etc.
Even for strings, the argument is correct: modern ones are better in every way, but they are still the same strings.
So in general terms, I would perform music on the instruments intended by the composer, with the sole concession that they can be modernly constructed instruments.
Question:
Why is it that when playing Poulenc's concerto for harpsichord and orchestra, no one dreams of playing it on the piano, whereas for Bach it is done habitually?