Q: This looks similar to another mod(s). Why bother create this?
A: While the GUI looks similar to Module Inserter, this mod is NOT a clone. There are several strong reasons that I decided to create my own, with the code written from scratch. Below are some main differences from the above-mentioned mod:

1. This mod simulates the player is placing modules into/from the machines directly, and assumes the player character is standing in the field. So it does not require putting in item requests nor calling bots. Hence, handling "item-request-proxy" is not ever needed, allowing a simple code.
2. The dual set (primary & secondary sets) is my original idea, in order to smartly handle recipes having module limitations or not. This will save a lot of user's time, as they can be handled in one go.
3. Assumes users update modules on-fly, as tech progress advances and more resource bceomes avaliable. (Say, the factory was using speed module 2 on everything previously, and now you are producing speed module 3 as direct upgrade.) So the "presets" feature in the above-mentioned mod is fancy but not useful to me.
4. More direct and cleaner controls. Same case for the GUI.