If you live without a vehicle in a rural corner of your state, compelling you to travel to somewhere else in order to get a state-sanctioned ID is, IMO, an undue burden.

If you are required to have documents and paperwork for a voter ID that you are not otherwise required to have, that is, IMO, an undue burden.

I have no problem with the state saying "you must have this document in order to vote" (it even makes a limited amount of sense, despite being a solution in search of a problem). I do have a problem with the state doing anything other than ensuring that every resident who should that document gets it with minimal effort (preferably zero).