You can set the LVP fuse to OFF and gain an IO pin because your programmer can do high voltage (13.4V) programming via the MCLR pin. Take note, that if you use the LVP programming mode, you cannot change the LVP fuse; you can only do this using high voltage (13.4V) programming mode.
High voltage (13.4V) programming mode will always be able to program the chip. If you disable the LVP fuse via 13.4V on MCLR, then you cannot program the device using the PGM pin.