Grid 19c: Purpose of QUORUM FAILGROUP on shared NFS mountpoint when you already have an +OCRDG diskgroup

I'm working somewhere now where every ASM diskgroup has been made with an extra disk under the QUORUM FAILGROUP option, and is built with the following pattern:

CREATE DISKGROUP stuffdg NORMAL REDUNDANCY
  FAILGROUP x DISK 'AFD:X' SIZE 30G
  FAILGROUP y DISK 'AFD:Y' SIZE 30G
  FAILGROUP z ...
  QUORUM FAILGROUP qrm DISK '/nfsmp/stuffdgdisk' SIZE 1G
  ATTRIBUTE ...;

But on all clusters they have over here, there's also a diskgroup whose sole purpose is to host OCR, voting files, ASM instance spfile etc. This diskgroup (let's call it +OCRDG...) is *also* built upon a similar shared drive visible at OS level (along with two regular ASM disks configured with AFD). Verifying this with CRSCTL QUERY CSS VOTEDISK you're shown the following:

[oracle@~]$ crsctl query css votedisk
##  STATE    File Universal Id                File Name Disk group
--  -----    -----------------                --------- ---------
 1. ONLINE   2b07d0a959d14fcbbf891f99e3bade87 (AFD:OCRDGD1) [VOTE]
 2. ONLINE   8943a8f2a8c64fc4bfaae430f45bc58d (AFD:OCRDGD2) [VOTE]
 3. ONLINE   1f166e30237a4f54bfabeb8d0ed63786 (/nfsmp/ocrdgd3) [VOTE]
Located 3 voting disk(s).

Listing all files under /nfsmp shows that since their creation, *only* /nfsmp/ocrdgd3 is used, all other files (like stuffdgdisk above) have kept the timestamp of their creation, months ago. My question: I've never used this configuration before (explicitly adding a quorum failgroup in regular diskgroups - I mean those used for data and archived logs destination or FRA), and obviously these files under /nfsmp (except for that which is used for OCR) are not used, so what is the point of this QUORUM FAILGROUP clause?? I've found the documentation very little helpful to understand this setup. Can someone enlighten me please? Thanks a lot. Regards, Seb