I would guess it's to appeal to the greater United States audience of readers, as at least in my experience most people live in an area where speeds are still measured in the hundreds of Mbps. This would allow for a more direct and distinctly dramatic comparison.
Obligatory reminder that the Third-of-a-Pound burger failed because people thought it was smaller than a Quarter Pounder, since it had a three in it instead of a four.
You get hundreds? I don't know anyone with that much. Although starting to see very expensive over 100Mbit options now, I use 4G as it's cheaper and more reliable which is somewhat amusing to be able to say.
I'm lucky enough to live over a business that allows me to use their Internet as a part of my lease, I do have 25Mbps. A marked upgrade from the non-business options in the area.
Because the way they write numbers is generally misunderstood in the west. Wan, the ten thousand character, and Yi, the hundred million character, are typically the crux of translating big numbers like this.
万 (wàn) comes up the most often and is the largest stumbling block for most people learning Mandarin numbers. In English, numbers are usually broken up into chunks of three digits. Because of 万 (wàn), it's easier to break numbers up into groups of four in Mandarin. In English, we split "twelve thousand" numerically into "12,000" (chunks of three digits). Split it the Chinese way, "1,2000," and the Chinese reading "一万两千" (one wan and two "thousand" = yīwàn liǎngqiān) makes more sense.
Not saying the figure isn't exaggerated, but holy shit it's obvious why it's translated this way in articles if you look even slightly beyond the surface.