The New Launcher vs Staging (Java versions mismatch)

The new Mojang launcher still uses Java 1.8.0_25 but the Staging one uses Java 1.8.0_51. Why Mojang still uses outdated Java versions? I know I can use the one I have on my PC (latest Java) but should stay secure with latest Java versions without Java installed on some computers.

So, why not use the Staging Java 1.8.0_51 rather the newly released launcher which uses Java 1.8.0_25? Or better using Java 1.8.0_121 (to keep it secure). I'm aware I can force it, but that could be nicer to have a recent Java runtime.

I'm running in a folder with the new launcher or the staging, causes a redownload the runtime everytime I test the staging or go back at the new launcher. I know too to run it on another launcher, but I prefer having all minecraft things into a folder (I'm aware if it can cause bugs).

PS: My english can be bad, im sorry =S