Once you can increase your inventory in the game, it will be much easier to collect all the items you find. You will have more ammo, items for sale, or additional consumables. The ability to store more than anything is a huge plus in the game.
In order to increase your inventory in The Callisto Protocol, you need to get to the Lost chapter and go through it about halfway. Here you will automatically receive an increased inventory and be able to store more items. For your information, at this point the game will be completed by approximately 60%.