there are two types of signal we are talking about: balanced and unbalanced.
Balanced is good because it generally is not effected by noise as much. To be balanced it need three connectors in the wire positive, negative and ground.
Unbalanced has two conectors, positive and ground. Signal degrades over long cables.
Typically unbalanced things like a bass use quarter inch jack sockets.
Balanced things use XLR .... but the important thing is what the signal is - not what the plugs are...
So in typical use a DI box converts a unbalanced signal to a balanced signal. It might also change the level and impedance but that's not relevant at the moment.
So you plug a bass (that gives an unbalanced signal) into a JDi - and it converts it to a lovely balanced signal - which you need a wire with three connectors for... so you use the industry standard XLR and take lots of lovely bass signal to the desk.... sorted.
If you look here at the back of the helix you can see two XLR out in the middle - sending balanced signal to the desk.
Where it gets confusing with the HX Stomp and HX effects is we don't have any XLR - for the same reason that my iPhone doesn't have a headphone socket - there's not enough space.
Instead we've got a 1/4 inch jack. ... which is what we typically use for unbalanced signals. BUT they have designed it so a 1/4 inch jack with three contacts (TRS) will get a balanced signal.
So a TRS - XLR cable will do the same job as a XLR-XLR out of the back of your JDI
A TS - XLR will give an unbalanced signal (and need a DI box to make it balanced)
So in your case if you are replacing the JDI with the Stomp you will need one (or two for stereo) TRS-XLR cables to send to the desk (or converters)
The downside is - that it's not a standard cable so you will need to buy them (and a spare) as you can't expect a venue to have them.
(In worst case senario though you can use a ts-ts and a DI box!)