Simply have a setting for a field in the same table to automatically update its contents based on the values in another field. This would be like you did a copy and paste of the other field column into it.
It's simply type conversion with both types persisting.
You'll probably have to make that field non-editable, like a synced field or else allow for 2 way syncing if you want to get elegant.
How does is solve the user problems?
So many of our automations are put towards the simple task of updating data in one field with that of another. Managing this slows us down and limits our use cases (especially with automation limits).
(1) This is especially important when making use of interfaces that limit the field types it can take advantage of for certain purposes.
(2) Converting Formula fields into single/multi selects or linked fields.
(3) Converting synced linked fields into a more usable format (a select or linked field)
(4) Converting discreet form data into other types. Example, NPS forms require discreet numeric 0-10 answers that require a select, but the results are not numeric and must be converted to be usable for us.
(4) There are tons of other use cases. Having to convert data types is ubiquitous across the platform.
How was this validated?
Who is the target audience?
I only chose fields because that is the core functionality we are discussing, but this will impact a variety of different parts of Airtable, including: Sync, Interface Designer, Base Design, Automations and Scripting, Formulas and Calculated Fields, Views and forms, and even improve ease of use for some extensions.