Odd title. It says estimated diameter is 150km, while Mars' moons are just 22km and 12.6km. That sounds like hundreds or thousands of times bigger, by volume and mass. (I calculate ~300x to 1700x the mass, if they have similar density) ...I'm taller than a kitten, but it's not very informative to say so!
"bigger than a Martian moon": That wouldn't be difficult. The martian moons are absolutely tiny. So tiny in fact, that some astronomers had even theorised that they might be artificial. (That was before we were able to actually see that they weren't.)
One of them is exactly the median size of a moon of a terrestrial planet in our solar system, the other is the closest moon of such a planet to median size that isn't exactly the median.
To me the most interesting thing is that they detected it and classified it as a potential dwarf planet, then noticed it was falling inbound. Closest pass to the sun 2031.