The acoustic bass works as a two-fold idea. On the one hand, you're able to provide the dry and percussive sound of strings on wood that perfectly backs lighter music genres, in particular a boon to folk players and singer- songwriters.
On the other hand, they’re a helpful practice tool for anyone who wants to hone their bass technique without needing to deafen their neighbours or be within range of a power supply. Much like an acoustic guitar, the choices you make when picking out an acoustic bass will be governed by your preference in terms of tonewoods (laminate or solid) for the body and neck, the size of the body itself and whether or not you need electronics.
In terms of the latter choice, a good electric bass amplification system can be included, offering tone-shaping EQ and feedback-suppression options. The goal is to be as comfortable as possible while playing, and to achieve a tone that you can use simultaneously for satisfactory practice and backing acoustic gigs.