For some reason, I hate those sliding handle locks that are on my ball valves but I never take them off or anything. Is there a reason why I don’t take those off? Are they doing something for me that I’ve never noticed and I will regret taking them off my valves?
The slide latch centers the opening of the ball with the opening in the housing.
Typically, in the home brewing scenario, the locking function of a ball valve is not necessary. In an industrial scenario, they would be used in a Lockout-Tagout situation providing the locking device has a hole that is aligned with a hole in the handle.
sweet! i will be taking those damn things off. Every time I go for a quick valve action, I end up hitting the lock. After 20+years, you think I’d have solved this by now.
They DO help prevent you from pouring boiling wort all over your work area and yourself 
They prevent you from opening the valve if you accidentally push on the handle. I keep them for safety reasons, but they mostly get in the way especially when I realize I left the valve open while filling the tank to which the valve is attached.
Perhaps simply tape the slide device in the up position to disengage it? I wouldn’t bother with it, but I see it as protecting me from inadvertent opening of the valve.
They also slow you down closing it when you knock your hose off the barb on the valve…
Sounds like you need hardware that has locking ability built into it (like a ball valve does)
…unless you’re one of those “safety third” kinda guys