Nope. MSFS and X-Plane may start as games, but you'd be surprised how widely they are used in professional aerospace and aviation for a variety of purposes. In fact, back when MS had the old Flight Simulator (disbanded in 2006,) they had developed and sold a parallel commercial version which was used in a variety of flight simulation and training platforms. It was this version that was sold to Lockheed Martin, which became Prepar3D, which--whether you agree or not--is explicitly licensed as "not a game."
Now, one could argue the differences between X-Plane and MSFS in terms of realism. From a professional point of view (airline pilot or aerospace engineer,) both are very much in the same general field. Truth is that neither of them meet performance requirements to be used in the kind of certified full motion flight simulators airline pilots use on the job, although both products arguably have components that are useable in those. However, both products are also highly extensible. Just because the out of the box models may not be super detailed doesn't mean an add-on product can't come with its own flight and system models--for instance, PDMG and FlightSimLabs produce airliners for the old FSX and Prepar3D that will outperform most everything on X-Plane from a realism perspective. Expect that their products will be on MSFS2020 in time.
Also, it's important to distinguish between flight model realism and systems realism. Both X-Plane and MSFS add-ons can and do come with their own flight and system models which replace out of the box componentry, but arguably it's the flight models that are more dependent on the capabilities of the base sim. Everyone complaining about the lack of realism in the MSFS stock G1000 implementation should just wait 6-9 months, and surely something better will be out.
From my POV, the new MSFS does 2 extremely impressive, arguably revolutionary things, and the aerospace/aviation industry has taken note: a) The photogrammatry rendering of the whole earth in high fidelity 3D detail, and b,) the representation of the real ATC airspace through leveraging ADS-B (i.e. FlightAware and Flight-Radar 24.) Simulating a single airplane to a high degree of fidelity on desktop hardware is easy. Simulating (I mean truly simulating) an airspace of airplanes is not... ATC in most sims--to date--is scripted, not fully simulated. Piping in the real world (and combining it with live multiplayer) is a very interesting alternative.
The visuals are not that relevant for professional training, it's much more about accurate instruments and procedures. On the other hand, in my multi-crew coordination training the first part was sitting in front of a cardboard 737 cockpit. That could also be done with a cardboard cockpit + 2 screens connected to MS FS. Because with cardboard only you have no time pressure, while if something is really "moving" you do have time pressure.
Now, one could argue the differences between X-Plane and MSFS in terms of realism. From a professional point of view (airline pilot or aerospace engineer,) both are very much in the same general field. Truth is that neither of them meet performance requirements to be used in the kind of certified full motion flight simulators airline pilots use on the job, although both products arguably have components that are useable in those. However, both products are also highly extensible. Just because the out of the box models may not be super detailed doesn't mean an add-on product can't come with its own flight and system models--for instance, PDMG and FlightSimLabs produce airliners for the old FSX and Prepar3D that will outperform most everything on X-Plane from a realism perspective. Expect that their products will be on MSFS2020 in time.
Also, it's important to distinguish between flight model realism and systems realism. Both X-Plane and MSFS add-ons can and do come with their own flight and system models which replace out of the box componentry, but arguably it's the flight models that are more dependent on the capabilities of the base sim. Everyone complaining about the lack of realism in the MSFS stock G1000 implementation should just wait 6-9 months, and surely something better will be out.
From my POV, the new MSFS does 2 extremely impressive, arguably revolutionary things, and the aerospace/aviation industry has taken note: a) The photogrammatry rendering of the whole earth in high fidelity 3D detail, and b,) the representation of the real ATC airspace through leveraging ADS-B (i.e. FlightAware and Flight-Radar 24.) Simulating a single airplane to a high degree of fidelity on desktop hardware is easy. Simulating (I mean truly simulating) an airspace of airplanes is not... ATC in most sims--to date--is scripted, not fully simulated. Piping in the real world (and combining it with live multiplayer) is a very interesting alternative.