First off all, you name the file that will keep your data and enter the secret password to lock/unlock it.
When you go to register Vault itself, it becomes soon your first key logged. That's what is expected from this kind of very specialized program, that it work for you.
Vault has a simple interface, and I was able to register all my software keys, except for one little inconvenience: in the notes field, when hitting the key the registration dialog is closed, however my intention was to add just a new line. So each time I needed a new line in the notes field I had to play a small cut-and-paste dance to get it.
I also would like to see an option to save a small licensing file together with my keys (for instance, like the one used by Hazel). There is no such provision in the current version 1.2.1 that I've used.
Other than that, in the preferences section there is option to clear clipboard after 'n' sec. (default: 10), to lock when system sleeps, and to make passwords visibles. These options I recognize as useful, depending of where you are working you might be interested in adjust their values.
It seems to me that the unique way to get keys/data into this program is by manually typing it, or using the clipboard to poorly interact with others programs. So Vault has it uses, but sometimes I just don't want to repeat the login/password from sites while browsing, mainly because I know that other password manager already has captured and registered this information for me.
Summing up, the program worked as advertised, and I will be using it to help keep me cool wherever I discover that I need to reuse one of its keys. But I will also continue using KeyChain Access due to its better integration with others programs (browsers and openssh).