Duanejc, the lead does play an important roll, firstly, the fish is hooking itself against the weight of the lead.
Then you have different leads for different lake bottoms, eg, silt, weed, gravel etc.
The shapes are designed specifically for a number of reasons, some are: to stop rolling, weight distribution on the hooklink, and then long distance casting leads, which are shaped to aerodynamically fly throuh the air with leaste resistance.
The conventional P type lead, can be used, but the hook up wouldnt be as effective due to it's weight, then, its shape could allow it to move or roll in the wrong application/lake bottom condition.
With comp style angling, I think they use them, or something simillar,but then the line only lies in the water for an average of 5mins and the fish caught there are much smaller than specimen target fish.
The camo coating isnt a necessaty, but it helps to mimic the lake bottom. I have underwater dvd's where they test the effectiveness of coated/uncoated leads and quite honestly there isnt a diff when it comes to hook ups. The fish dont say oops lead lets not go there, or hey nice camo lets go closer. But in general, all leads, coated or uncoated make fish skittish. (kinda a win no win situation)
Ive heard of guys taking new leads and dropping them in vinegar/lemon juice to tarnish them, so they noe shiny.
I cast my own leads and I have two camo powders a greenish one and a brownish one, if I know where im angling, i coat them accordingly, even mix the two colours sometimes. (Its easy to apply and ...hehehe! they look good. giving ME the confidence)
As a matter of fact, the inline leads we buy in tackle shops arent that safe.... a true inline lead, has a slit on the one side thinner than the plastic insert,the insert clips on the swivel. so, if it does snag, it slips off the insert and off the leader. This will only happen however if the fish is pulling your line, as the lead moves up the line.
So Duanejc, its technical lol....