Plastic eraser vs Rubber eraser
The &quot;rubber&quot; eraser you linked to actually looks like a plastic eraser.  &quot;Rubber erasers&quot; typically refer to the type on the end of a wooden pencil or a block like the Pink Pearl eraser.  There are many other types of erasers; I'll focus on just the two in the question.
Just an interesting historical aside, the first erasers were made of rubber but the &quot;rubber&quot; in &quot;rubber eraser&quot; comes from the fact that when erasers were invented by accident in the late 1700's, the term &quot;rubber&quot; was in common use for any object used for rubbing[1].
Rubber erasers aren't usually made from natural rubber any more.  They're a rubbery plastic or synthetic rubber that contains a lot of plasticizer and some abrasive filler material, the amount of which varies.  Rubber erasers are generally good for pencil lines, although the surface can get saturated with graphite and then start smearing it around.  Decades ago, ink erasers were rubber erasers with more abrasive.  They were harder and erased the ink by sanding away the paper surface.
Plastic erasers are a soft, rubbery plastic, often vinyl, with no abrasive filler.  They are generally better than rubber erasers for most purposes.  They erase pencil marks more effectively and with less tendency to smear.  They can sometimes remove ink marks without tearing up the paper surface.
I've come across articles like the quote added to the question, that claim plastic erasers are hard, or they more easily tear the paper.  I've used them for probably decades and have no idea where those claims come from.  Plastic erasers are more effective and require less pressure and rubbing.  The paper is more likely to be damaged by using a rubber eraser that smears the pencil marks, then requires more aggressive rubbing to clean it up.
The plastic erasers tend to be more expensive than the rubber erasers.  It's possible that they are more expensive to produce, but I suspect pricing is based on what the market will bear and the size of each market.  Rubber erasers are adequate for school and a lot of general office and personal use.  Plastic erasers are more in demand for more critical applications like art and drafting, where users will spend more for better performance.
Buying single erasers often carries a huge price markup that has little to do with the manufacturing cost of the eraser.  If you buy packages of three or more, or especially, a bulk box of 10 or 12, you can often get a lot of erasers for what you would spend on a couple of individual erasers.  Even if it takes you a long time to go through them, the initial purchase won't break the bank.
I'm not sure of the monetary conversions for the prices in your links.  Looking at prices in the US market, you can easily find packages of two or three rubber erasers at around $0.50 per eraser.  In-store at a retailer like Walmart, you can get a package of two for less than $0.50.  For the plastic erasers, you can find bulk packages of 10 or 12 at $0.50 per eraser, like these brand name erasers through Amazon.