CBDA is the acidic precursor to CBD (just as THCA is the acidic precursor to THC). Like with THC, CBD is not actually produced directly by the plant but instead cannabis plants produce CBDA, which is converted from CBGA by

enzymes in the plant.
The CBDA converts to CBD through decarboxylation which can occur gradually at room temperature (though this occurs at a very slow rate) but can occur at a faster rate through the application of heat. Like with converting THCA to THC, the recommended optimum temperature range for rapid decarboxylation (with in an hour) is between 110c and 130c, however CBDA is believed to require slightly more heat/time to decarb than THCA (though still with in the same general range). This is evident by test results on cooked cannabis extracts where THCA conversion to THC is complete but CBDA conversion to CBD is sometimes not.
Like with other cannabinoid acids, compared to the neutral counter part CBDA has not been subject to a lot of study. However it has demonstrated potentially significant anti cancer effects in a small number of studies and appears to surpass THCA in this area. Like virtually all cannabinoids and cannabinoid acids it has significant anti inflammatory properties and is also showing promise as an anti nausea compound with both anti emetic effects and nausea preventing effects demonstrated.
It is also believed to have strong anti bacterial properties, though this is not as well established.

Although there is no clinical or preclinical data to support this currently, anecdotal reports suggest potential for CBDA as an anti seizure medicine similar to THCA. Many epileptic patients reporting greater efficacy from using raw THCA than high CBD extracts are reporting similar efficacy with raw CBDA extracts. Though this lacks clinical confirmation at this time.

The anti cancer effects of cannabinoid acids are not as well established as the anti cancer effects of the decarboxylated/neutral cannabinoids, but CBDA is among the more established of the acidic cannabinoids in this area with a small number of studies demonstrating anti cancer effects. Like THCA it has affinity with the receptors TRPM8 and TRPA1, in addition to a strong selective affinity with COX-1 and COX-2 (which also contributes to the anti inflammatory properties). In addition to this CBDA has demonstrated significant anti cancer effects through other pathways that suggest potential for it to be useful as part of a treatment protocol for certain cancers, breast cancer currently looking the more promising area for utilising CBDA.

The anti nausea effects have been studied more lately and have shown promising results suggesting that it may be able to rival THC as an effective anti nausea medicine, with out the psychoactive effects associated with THC. Both nausea relief and prevention have been demonstrated in a small number of studies, with activation of receptor 5-HT1A considered a key factor.

Like with THCA, CBDA is also believed to be very beneficial for Lupus, though like THCA such benefits are consigned to anecdotal evidence at this time. CBDA is capable of interacting with many of the receptors that THCA has affinity with (like TRPM8 and TRPA1) but also has affinity with other pathways that does not apply to THCA (TPRV1 being a good example of this) so may offer a wider range of benefits, though until more research is done on the cannabinoid acids (and cannabinoids in general) it is difficult to gage its efficacy in comparison to other cannabinoids.