As has already been stated, the Bassbreaker line is actually geared towards guitar players, not bass players.
While the Rumble 15 is a great amp for learning how to play (my first bass amp was also a 15w 8" Fender, but I don't remember if it was called a "Rumble" a few decades ago

) you will be blown away at the difference in depth, clarity, and feel of something with 100+ watts and a 12" speaker or two 10" speakers!
The Rumble 100 or Ampeg BA210 (the Ampeg is on sale at Guitar Center or Musician's Friend for Memorial Day, I believe!) are great, affordable choices that will serve you well, while not taking up TOO MUCH real estate at home!
You stated you don't have ambitions of joining a band or anything, but I hope that you DO get to share in playing/making music with some buddies at some point! If you DO start playing out a bit, you may find that separates (a head/amp and multiple speaker cabs) provide better sound and more flexibility down the road.
Sweetwater is a great resource, and one of my favorite e-tailers. They also have buying guides that are useful in explaining the basics of which does what, and how they are related/used together.
Bass Guitar Amps | Sweetwater
Bass Guitar Amp Buying Guide
Good luck, and we look forward to hearing more about your journey!