Its simple nature makes it straightforward to understand, implement, and diagnose, while its low voltage means it typically runs along relatively thin cables.
Because each device has its own wire to the controller (rather than being part of a network) it has no need of an address to be set, so can be replaced simply by unplugging the faulty one and plugging in the new.
It dims to off, so does not require mains switching equipment to turn them off.
DALI is an open standard for digital control of lighting. Several companies have adopted the DALI protocol in their product offerings. Even though DALI is an open standard, there are already versions of its implementation emerging in different lighting manufacturers products as they strive to provide a point of difference. DSI is essentially the same technology as DALI in terms of messaging, however, DSI eliminates the individual addressing aspect of each light fitting found in DALI.