The reason I am requesting to add this user input type is for the following case:
I want to duplicate a quote and right now I ask for the new Quote Code but I want to ask to which project that code should be added in since in some cases the quote can be duplicated for different projects It could be solved using a text field but its possible that the entered code is incorrect.
Which is why I would rather use a lookup field that displays a list of projects so that the user won't enter the wrong project and can easily find the project they are looking for.
I believe that there are a lot of cases out there that really could be solved with this new user input type.
I really hope that this will reach the roadmap one day!