Actually players have to use the inventory screen to store attachments, use stored attachments, and swap attachments for equipped weapons.
Right?
Additionally, some players hold weapons (with no hop-up option), from a specific ammo class, until they can switch to a preferred weapon later in the game. For example, a player might on hold to a Volt until they can find a Nemesis.
Lastly, all other loot pool items can be stored. I don't think storing hop-up boosters is that complicated of an issue. 🤷♂️ I respect your opinions though.