2.DMX has industry standards, and SPI is generally customized by manufacturers. DMX lamps should be more compatible.
3.DMX is address selection and dimming signals are input in parallel; SPI is generally serial forwarding. So the former has no single point system failure, but the address capacity is a problem.
According to my years of experience in making DMX5 12 dimming LED lamps, DMX5 12 lamps are highly reliable mainstream and will be expanded in addressing in the future. You can search for "universal DMX5 12 decoding chip" in Baidu Library.