Here's another reason ...,

You can't turn GIE off. If you do, it jumps to the handler then turns GIE back on.
Code:
LED1  VAR PORTB.0

ON INTERRUPT GOTO MyINT

Main:
    PAUSE 500
    INTCON.7 = 0
GOTO Main

DISABLE
MyINT:
    TOGGLE LED1
RESUME
That will flash the LED via the Interrupt handler, even though no interrupts have occured.
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