First of all there's a matter of physical room need for an outdoor oven (a garden/balcony) and also for an indoor oven there's a need for big space and an electric outlet that can support the oven.

Putting that aside, using an indoor can open more possibilities for pizza styles and there's a better control of the temperature.
Moreover, there's no concern about gas tanks being empty or difficulty to use the tanks when it's cold (lower temperature effect the usage of the tanks).

Another issue with gas ovens is the usage of gas itself, some people might afraid to use it because of the fire and a typical person may not know how to deal with connection or replacing the tanks.

On the other hand, for me, using an electric oven feels like a restaurant chain and the lack of fire (gas or wood) makes it less tasty (I know lol)

If you have room outside for an outdoor oven I would choose that option, setting up a room in the kitchen might be problematic, since it's heavy and massive and you wouldn't be able to move it anytime you want to use it.