Do I need PTR RRs?

[ccantu at us.ibm.com]

If I have a printer and everyone sets up their print queues using its IP
address -- then if I have an A resource record for that printer, they'd be
able to use the printer's FQDN to set up the queues, right?  But I would
have no use for a PTR RR unless I ever wanted to do an nslookup of that
printer's IP address, right?  The questions:  Is there any significant
disadvantage to not doing the PTR RRs in this case?  In what case would the
PTR RR be a necessity?

Carlos