Yes, just as the choice of an exponential should be justified.
Most research papers at least do this as far as explaining why pick an exponential over a linear regression, which I think is a good practice because in many applications picking something other than a linear regression results in better fit of past data but worse fit of future data. But the point stands that needing to justify a sigmoidal or sigmoid-like model is the same problem as justifying the choice of an exponential.
Yes, just as the choice of an exponential should be justified.
Most research papers at least do this as far as explaining why pick an exponential over a linear regression, which I think is a good practice because in many applications picking something other than a linear regression results in better fit of past data but worse fit of future data. But the point stands that needing to justify a sigmoidal or sigmoid-like model is the same problem as justifying the choice of an exponential.