Fair point. My view is that even of it's only 5-10% more enjoyment, then it's worth at least trying a balanced cable, otherwise what's the point of paying for a DAP that has the option. I appreciate there are other reasons for buying one DAP over another, but there are very good DAPs that are SE only, or things like the Chord Hugo and Mojo that don't offer the option.
Personally I can always tell the difference: balanced out on Glove A1 with my old AK120, or the Onkyo DP-X1, and now the X5iii.
For what it's worth, one of the deciding factors for me getting the ALO CDM, apart from liking the tube sound, was the balanced out (I was using it OTG with an IPhone originally, so I obviously got an improvement in SQ for a number of reasons, including the better DAC and tube sound, not just the balanced output; but I'm also enjoining using just the amp section of the CDM with balanced out with the FiiO).