I think tube amps are overrated for bass players - for guitar players they are more important. They are not essential for bassists. Just my opinion.
Now that you didn't listen to anyone and bought the Fenderyou should figure out how many speaker cabinets you can safely drive, and get the maximum. I usually don't think 100 watts is enough for bass, but I've heard people say that with a lot of speakers working, 100 watts can do fine. You want as many big speaker cabinets as possible, especially with a lower powered amp. At least one 8x10 if possible, at the minimum. More if the Fender can handle it!
Why would they be more important for guitar than bass? I think it more depends on what kind of sound you want.