Are one-click methods "safe"?

Hi all, I have a noob question. I want to know if I use a one-click root method like Towelroot or Kingroot, will they have "access" to my phone? In other words, will passwords and the like be stolen from me? Is one method better than the other. I tried searching for an answer to this question, but to no avail. Please forgive me if this was already answered somewhere!

Thanks in advance,

thejediknight
Galaxy S4 i545
Verizon, unrooted running Lollipop