Why? Its what the F6F did. It was a zero killer and was very effective against ground targets because it could carry a heavy payload.
Standard armament on the F6F consisted of six .50 in (12.7 mm) M2 Browning air-cooled machine guns with 400 rpg; later aircraft gained three hardpoints to carry a total bombload in excess of 2,000 lb (900 kg). The center hardpoint also had the ability to carry a single 150 gal (568 l) disposable drop tank. Six 5 in (127 mm) HVARs (High Velocity Aircraft Rocket)could be carried; three under each wing.
The next and most common variant, the F6F-5, carried the standard six .50 in (12.7 mm) machine guns. Trials with cannon-armed Hellcats were not followed up by a production version; although all F6F-5s could carry an armament mix of a pair of 20 mm (.79 in) Hispano cannon, one mounted in each of the inboard gun bays, with a minimum of 220 rpg, along with two pairs of .50 in (12.7 mm) machine guns, with 400 rpg, this configuration was only used on many later F6F-5N night fighters.
The designated armament for the F6F
Guns:
either 6× 0.50 in (12.7 mm) M2 Browning machine guns, with 400 rpg, (All F6F-3, and most F6F-5)
or 2 × 20 mm (.79 in) cannon, with 225 rpg
and 4 × 0.50 in (12.7 mm) Browning machine guns with 400 rpg (F6F-5N only)
Rockets:
6 × 5 in (127 mm) HVARs or
2 × 11¾ in (298 mm) Tiny Tim unguided rockets
Bombs: up to 4,000 lb (1,814 kg) full load, including:
Bombs or Torpedoes:(Fuselage mounted on centreline rack)
1 × 2,000 lb (907 kg) bomb or
1 × Mk.13-3 torpedo;
Underwing bombs: (F6F-5 had two additional weapons racks either side of fuselage on wing centre-section)
2 × 1,000 lb (450 kg) or
4 × 500 lb (227 kg)
8 × 250 lb (110 kg)
In the ground attack role, Hellcats dropped 6,503 tons (5,899 tonnes) of bombs.