These both come – cheaply – from H & M and have been fantastic travel companions over the years.
You can see exactly what is inside them, the plastic from which they are made is very thick and sturdy, the double zipper pulls add extra functionality (you can open them up just where you need to get something out) and there are no non-waterproof fabric elements anywhere.
When you travel, particularly long flights or road trips, your bags can be bumped around. Bottles can break, flip tops can open, things can leak. These bags will contain all spills and smears, and can be wiped clean.
I also use similar H & M makeup bags in my handbag. They do attract scratches so I tend to replace them every three months, but they are completely watertight and you can find things easily.
A cosmetic bag like this one would not work at all, because it has a non-waterproof fabric element at the top, and a gap between the zipper and the bag. On a long trip with a lot of bumping around, any escaped liquid or cream would soak right through.
We have recently done 2 x 14-hour flights and a 3000km road trip and the bags at the top of this post came through absolutely smiling. One spray bottle lost its top but the spill was contained and could be wiped away in a minute.