Yes it is that. You are creating an image of the building before it has been built to show people, who cant read plans and elevations very well, how that building will look when its finished. Its definitely a very creative art in that the best images have something story-like about them. But tbh most of the work you get here in UK is illustrating houses as quickly and cheaply as possible, sometimes apartments, industrial units or offices. Very rare to get something like a museum or airport - they usually only go to the large firms! But if you find a niche you can do some nice stuff. One person here does images that look like watercolours for example and seems to be very successful. If you want to do this successfully maybe investigate the history of architectural illustration and see what you might like to do in terms of establishing a style. But just doing photorealistic illustrations is a bit run of the mill now - loads of people can do them. But not everyone has the artistic flair required to produce a form of 'art'.
But like all arts, including architecture in many respects, the salary is low compared to other non-artistic jobs. Everyone wants to get into art or sport or music - no-one wants to get into accounting, IT or quantity surveying. This is why salaries in those other professions are so much higher. And why you really need to excel if you are to get into an artistic career.
This, along with the learning curve, is why I said you are best exploring another career to supplement your income whilst you learn and establish yourself in archvis. For example I am an architect - I do certifications of buildings to supplement my archvis income and previously all me income came from being an architect. If I wasnt doing that I wouldnt be able to live. I see archvis as more of a hobby that may take off at some point and may not. That probably the best way to look at it unless you are extremely dedicated and very creative (or rich).