Honestly, I did buy a bass with the intent of learning, but due to a mixture of a lack of time and attention I haven't touched it as much as I would like.
It might be easy to learn where the notes are and move your fingers around - e.g., compared to guitar you are far less likely to play chords. But to make it sound good is definitely to just hitting the right notes and playing in time.
If you want to sound good at ANY instrument you need to learn its nuances and subtleties. Muting the unplayed strings is vital on a bass guitar, and using the correct intensity and playing technique to get the best tone.
Now, personal experience: Bass is a really fun instrument to play around with, and it's easy to improvise a little and develop correct techniques at the same time. Keep the string muting as a priority right from the beginning and you'll be off to a really good start. And like all instruments, true mastery requires a hell of a lot of work and dedication.