The veneration of relics might be revolting if viewed from a pure anatomical point of view. But there have been many miracles associated with them. Much like the woman who was healed by merely touching the hem of His garment. It is all the Grace of Jesus Christ, yet even so, He takes delight in bringing about healings that are associated with His closest friends. Not because they are distinct from Him, but because their Christian example was heroic, and we are called to imitate them, as their perfect Charity is the one virtue that Jesus Christ expects of us, more than any other virtue.
In the realm of learning, some people are more auditory learners, others are more visual, some really benefit from tactile experiences. Saints relics as far as I am concerned are nice reminders that I belong to the family of God. It is no different than when my beloved Grandfather’s effects were being distributed, my mom asked if I wanted his professional engineering certificate, which was in a handsome metal frame. I got all choked up reading the certificate, as I was one of a few of his grandchildren who had gone on to become an engineer. It was a stupid little piece of paper, but it brought to mind so many memories. As I pray my way through this life, I have been blessed with the company of the Holy Family and many of my favorite and patron saints. If I were to obtain a little piece of thread or chip of bone that was associated with any of them, I would be happy to have such relics, even if someone else might think it silly.
For example, I was blessed to have the opportunity to visit Notre Dame Cathedral this last June. Being a first Friday, we had the opportunity to pray before THE Crown of Thorns. You know, the one that Jesus Christ wore on the Cross. It was displayed behind a sheet of red glass about five feet from where we knelt. It is only a bunch of twisted vines, most of the thorns have been broken off and shared (~70) with other Catholic churches throughout the world. But it was a very poignant moment for me. He worn that crown for me, He died for me alone, it was my sins that put Him to death. And there I was mere feet away from that horrible item of torture that He wore out of love for me. The Crown of Thorns is another Catholic relic, some might say we don’t need to see it or kiss it or contemplate in its presence, but for me it was a truly blessed moment.
People ‘choose’ where they put their faith....be it in something they 'believe' has power... they ‘touch’ or what they ‘see’....in order to create an anticipated experience by such an attachment,... or something more than the sufficiency of Jesus Christ and what he has accomplished...... Yet Jesus said “Blessed” are those who believe without seeing. .and that our faith is increased in this manner ...”Faith comes by hearing and hearing the word of God”.....
Relic worship/venerating isn't necessary....in fact as you said, with dismembered body parts, it certainly can be seen as ‘revolting’......and I'll add health risks. For the Christian faith I practice to even think there is power in dismembered body parts is like believing ‘in channeling’... practiced by soothsayers/magicians and their lot.