Hi Res can definitely make a positive difference - I have some Naim recordings in standard Red Book and either 96kHz/24bit or 192kHz/24bit, and the hi-res versions demonstrate better and finer detail resolution, and unquestionably better spacial resolution. But, those are all very well recorded and mastered recordings, where the original master was natively hi-res. I have plenty of other hi-res recordings which are, in comparison to original CD format, no better in terms of resolution, and often musically bowdlerised. Among my worst purchases is a 24bit/96kHz download of Steely Dan's Gaucho - as dull as ditchwater, but maybe that describes the album. It's not just digital, though: last year curiosity led me to buy a copy of Carole King's Tapestry, expensively re-issued on two 45rpm records by Mobile Fidelity - superficially 'nicer' sound but musically less engaging than an LP copy bought sometime in the early 80s.
Ultimately, the quality of the original recording and mastering is what matters most, and not whether it's hi-res.