Why should I install both 32 and 64 bits Oracle provider for the same machine?
As alluded to in the question you linked to, some SQL Server tools/applications are 32-bit only. The main SQL Server application (sqlservr.exe) is 64-bit (32-bit may still be available as well, not certain about that for the latest versions); however, some of the supporting tools, perhaps most notable SQL Server Management Studio (ssms.exe), are only available as 32-bit applications.

If you want to install both versions, this should be sufficient reason.

If you want to find out if you can avoid installing the 64-bit version, all I can suggest is uninstalling that version from your development environment, and confirming whether or not everything still works as expected (including SSMS, and any other applications you use). If everything works fine, you can probably skip installing the 64-bit version in production. If you have problems, assume you need both versions.