SUMMARY:
It doesn't have the 3 second delay.
It ORs the result bits with the actual bits to combine them and turn them on.
Its for bits that can be combined that don't override each other.

Example games that use them:
1.  Silent Hill 2 and 3 can have any combination of bits turned on to get items and weapons.  No item or weapon makes others disappear if another item is present.

An example:
0042dac4 00000085 (your result)
0042dac4 00000012 (what is currently on)
85 OR 12 = 10000101 OR 00010010 = 10010111 = 97 (what will be turned on).

							    a
200ffc60 8f0d0004 lw t5, $0004(t8)            Loads the address you are testing.
200ffc64 930b0008 lbu t3, $0008(t8)           Loads your result bits.
200ffc68 91ac0000 lbu t4, $0000(t5)           Loads which bits are currently on.
200ffc6c 016c5025 or t2, t3, t4               Combines the bits.
200ffc70 03e00008 jr ra
200ffc74 a1aa0000 sb t2, $0000(t5)            Stores the combination of bits.