You have discovered a basic principle of theory: Make your theory only as complicated as it is necesssary to explain the phenomena you want to explain. It is also known as Occam's Razor.
It results in models. Models are analogous, simplifying: They basically say that things would work like something else in some aspects (the simpifying part), but in another sense different. That is why a model must contain the actual explanation by analogon as well as a commentary for the differences. See the last chapters of Empiricism and the Philosophy of Mind by Wilfried Sellars, where he uses this picture.
Coming to the problem of electrons: The circular-path model, as you call it, has been used to explain two phenomena: 1) Atoms are not solid 2) They have a massive, positive core and small, negative charges around it with a really big deal of nothing in between. That is the problem Ernest Rutherford had been confronted with. What is more obvious than using a model that looks like the sun and its planets?
For understanding some phenomena, this model is enough. And it has one striking feature: It is easy. Why using a more complicated model for explaining phenomena that become perfectly understandable using this one?
I think Rutherford knew very well that his theory was flawed, as Maxwell's equation were about 50 years old back then, but nevertheless the success of models also depends on how well they can induce/use familiar pictures as mere illustrations. The model could intuitively explain a whole lot of things and others not.
So the question is not if the model is wrong (every model is to some extend, see below), but whether it is able to convey a picture that makes it easier to grasp an idea of how atoms may look like if we could look at them, considering the empirical data/phenomena we look at. What Sellars calls the commentary part of the model would have to include that the atom is not just a planetary system with an electric field instead of a gravitational one (reasons provided by @JoWehler). It would have to state in which respects the powerful picture is a false one.
Now, if you wanted to explain more phenomena, you would have to develop a more complicated model, which explains all of them (@JoWehler's answer talks about this). But the more complicated, the more abstract and harder to understand it will become, up to the point of being essentially useless for illustrative/explanatory purposes. If you want to explain something, using something nobody understands does not do the job.
I think your teacher is rightfully only using this easy model. Because explaining it in the more modern models would involve higher mathematics and a really high level of abstraction and knowledge. It would not use a nice picture everybody knows as illustration. The most advanced models involve equations that aren't fully understood by more than a handful people worldwide and cannot be visualised very well. It is coherent with the phenomena/data (or so they say), but it cannot explain anything but to a handful of people.
And now the point behind all this: Even the latest complicated, scientific, sophisticated model is still...just a model. It basically says "Insofar as we can measure and interpret the data (up to now), what we call atoms behaves like the variables in this equation the solutions of which look like this in the case of hydrogen" and the like.
It is how we are able to make sense out of what we see and measure. It is not what it actually and finally is and 'looks' like without question. This would not even be a scientific theory, see Popper's falsifiability. And models by definition have to be more crude than the theory behind them, otherwise they could not fulfil their illustrative/explanatory function.