Being able to carry 200kg doesn’t necessarily seem like a small amount, and yet the bags fill up quickly, especially if you pursue your gathering passion. The load you have to carry can be increased from level 10, because then the first bag equipment slot is unlocked. At level 30 and level 45 you’ll get another one each.
Bags are plentiful in the game, either you make them yourself or buy some at the trading post.
Here’s a tip: The bags, like armor pieces and weapons, can have affixes that allow you to get more Azoth when you loot some, for example, or reduce the weight of ores in general. So pay attention to that when you decide to buy bags!