using a pfile containing just the one parameter. Therefore, you generated an spfile containing just that one parameter. This is why that is what you see when you query v$spparameter. However, your running instance was started with a differnt(complete) parameter file, which is why
create spfile from pfile='something_or_other';
shows a different path. That command does not read any file, it shows you what is currently in effect.
sho parameter spfile
edit that as you please
create pfile='some_file_name' from memory;
and re-start the instance.
create spfile from pfile='some_file_name';