Star Trek Phaser Auto Destruct

Some thoughts about the Star Trek phaser's overload function. My main question is why did the overload function exist at all. If it was a hack by the users, why wasn't it corrected by the engineers in future editions. I mean, I remember the captain self-destructing phasers in the first Star Trek, but Riker, Wharf and others were destructing phasers still in the Next Generation.

Initially, I thought I could understand why the phaser would need a self-destruct, but since it is already a weapon of undefinable strength, namely the kill function, and the rock warming function, I can't understand why anyone would really want to blow it up.

Also, as my friend JR pointed out, could you imagine the liability insurance the phaser manufacturer must have had to pay to sell that thing to the federation? The costs must have been astronomical. I wonder, did the first edition phaser have the timer on it, or did people just blow themselves up.

Furthermore, what did the product request look like, "Dear Engineer, We'd like to add a self-destruct function to the phaser. We know we can kill, destroy, or stun anything short of a Romulan Space Cruiser, but we really want to blow ourselves and everyone around me up." What kind of request is that? Why would Starfleet, an otherwise very intelligent and benevolent group, albeit with lax rules around the prime directive, allow such a weapon to be given to its people.

Well, maybe they had Aflac and there are no lawsuits in the future. Still, I'd be worried that the Ferengi would sue the Federation over the use of such dangerous weapons. They would certainly interfere with their pursuit of Gold Pressed Latinum.