If you practice bass for one hour a night, then that is one hour less that you will have to practice guitar. In the LONG RUN, learning bass WILL help to reinforce your knowledge of harmony and the fretboard, and maybe improve your awareness of rhythm if you play with a drummer regularly.
If you are just starting out, then yes, it will help to develop strength and co-ordination in your left hand (if you are right-handed) for guitar. But once you have reached a very basic level of technique it won't really help so much any more. It definitely wont help improve your legato playing, picking, bending, sweeping, improvisation, chord playing, scale knowledge etc
Also, you're ignoring the fact that right hand technique for bass is 100% different from guitar, and will take up a lot of your time to develop.
I'm currently teaching myself bass from books and from listening to records that I like, as some friends asked me to play bass for their band back in October. I've made decent progress but it has definitely eaten into my guitar time, and I can't really say that it has improved my guitar playing. In fact I definitely do a lot less improv and transcribing for guitar than I would like to be doing.
That said, I think that I have been able to learn bass very quickly because I already played guitar to a semi-decent level, ie knew my scales and modes intuitively in the CAGED system and had spent years transcribing music and playing in bands.
That's my experience anyway, so take what you want from it. Although if you are just starting to learn guitar I wouldn't recommend attempting bass at the same time, as it could be a very long time before you see results on either.