Hot backups

If a tablespace has 2 files, is the foll backup methodology valid?

alter tablespace APPUSER begin backup;
host copy G:\APPUSER01.DBF F:\backup;
alter tablespace APPUSER end backup;

alter tablespace APPUSER begin backup;
host copy G:\APPUSER02.DBF F:\backup;
alter tablespace APPUSER end backup;

Or should we always back it up as

alter tablespace APPUSER begin backup;
host copy G:\APPUSER01.DBF F:\backup;
host copy G:\APPUSER02.DBF F:\backup;
alter tablespace APPUSER end backup;

Both methods are valid.

However, if you intend to backup both files during the same "backup session" (i.e. one after another right away), then I see no reason why one would use method 1.

Thank you.

I have recently "inherited" this database and dont know why they have set it up like that. The APPUSER tablespace has over 50 datafiles and the backup script goes over and does this thing 50 times...