DI is essential for plugging into a PA or desk for providing a balanced signal with the correct impedance. Multi FX are great for making awesome space noises and such.
Some fx units will provide a line level signal, which is louder than standard bass/fx pedal outputs, which might be the right impedance, or balanced, or not.
I think the original Zoom B3?has a dedicated DI output as well as a normal 1/4” output, so that might be worth looking at.