Exactly, allow me to add something to the list.Nope. The list of reasons could be endless, but a few of the more prominent factors are as follows:
Roots of the different plants can easily intermingle stunting growth.
Plants will actively be fighting for water and nutrients if a pot is shared.
In the event of infestation and disease, it is hard, if not impossible to isolate the problem plant from healthy one before the issue spreads.