Are you talking about Function parameters?
Do you mean predefined lists with fixed values (for example, color names, blend modes etc.)? Or custom lists, where you enter values yourself (for example enemy types)?
I can see how custom lists may be useful in some cases. Say, when you are calling "SpawnEnemy" function, instead of typing "zombie" in function parameter, you can select "zombie" from the drop-down list. However, there is a serious problem - you will lose the ability to enter expressions in this field, for example choose("zombie", "vampire").
It seems pretty clear with the image above but yes, we're talking about a parameter type for built-in functions.
I don't understand your example to be fair, like, if you want to have a text field, you just select the string type and you'll have it, this already exist.
What we're talking here is, like in the image above, a list/switch/enum type of definied choices you can set, in order to have a better workflow working with it, like in the image (for selecting the ease function in this case)
And I think you got it wrong saying 'you can enter in a textfield' because this isn't about that.
This system will help a lot if somehow you have to refactor a lot of functions, as in the call of the function, you'll have selected a specific id from that list, you can then rename them, reorganize them, without having to go back 1 by 1 on each function call and rename your call properly. (Kinda like when we had the old functions and params that were a mess, it was just awful to go back on all your calls to change everything, and this has been solved now)
This system will also be useful if somehow, these lists could be linked to an enum type file, which then can be imported in that list from this function. This would definitely be helpful