I think the niceties of different marques of gearing are well beyond a beginner. Well, a beginner like I would be. I know there are folk who want to do tonnes of research and look at all the niceties before they buy anything, but I fear you can end up putting a decision off for ever that way. To me a beginner (a real beginner, not someone who already cycles and wants to choose their first 'specialist' bike, be that road, or MTB or whatever), needs a bike that works, probably under a less than perfect maintenance regime, doesn't weigh so much that it's off-putting, and has some scope for personalising and tweaking as the person gets to know it, and their own abilities. And 'cheap' bikes can fit that bill very well - my first 'grown up' bike, the one I brought to York with me, and the one I got into cycling on, was a
Halfords ladies town bike - cost me £120, about 10 years ago. As I learned what was good and bad about it, bits got replaced, and by the time it was pinched it was exactly what I needed for everyday about town riding. By then I also had a classic tourer and a lightweight racy tourer, and had my first eye on recumbents.
But 'cheap' is indeed relative. I still regard £250-300 as a significant outlay. To me, a 'cheap' bike is a £59.99 special from Asda, and I wouldn't recommend it to anyone.