One thing that bothers me and I don't understand is why is the wallet set to mint 10% od PIV to zPIV. Shouldn't that be the choice of the user exactly how much of PIV one wants to convert to zPIV?
Like a textbox where you enter the exact value of zPIV you want.
You can control zPiv staking. Just add enablezeromint=0 to your .conf file, and then create as many, or as few, zPiv as you wish through the GUI.
That said, I agree the option could be made easier, and many people feel the same as you. Long story short, Zerocoin protocol relies on mixing your zPiv with a bigger pool of other people's zPiv, so that when you pull your normal Piv back out of the pool it's not possible to identify whose are whose. If the 'mixing pool' contains only a few zPiv, it's much easier to tell which ones came from where; conversely, if the pool is large, it is effectively impossible to tell, resulting in a truly anonymous system. Thus, the privacy of the overall network relies on the collective pool of zPiv being large, which is why the devs requested that everyone keep at least 10% of their total as zPiv. Anyway, as with anything like this (e.g., organ donation?), you have to decide whether to make it opt-in, in which case you don't piss anyone off but all the lazy people will just not bother opting in even if they're actually fine with it, or opt-out, in which case you piss off some people but most of the lazy and indifferent ones again don't bother opting out, so you end up with wider compliance. Obviously, the devs chose the latter option. The point is there is a very logical reason for the 10% zeromint thing, but yes, it annoys some people, and yes, you can turn it off, and yes again, arguably the option to turn it off should be made accessible through the GUI.