Honestly, I don't get it.
I think some do it because they want their child to be unique (because obviously having a unique name makes your kid sooooo special...).
...but while they think it is unique and special. I just think it makes the parents look stupid and uneducated...and I feel bad for the kids.
Changing a spelling of a name does not make them unique! When someone says little Jaxsynn, Ryanne, Alexys, Quatherynn, or Jayms' name out loud...it "sounds" the same as Jackson, Ryan, Alexis, Katherine/Catherine, or James. In addition to having that popular name (not an issue, really), they also have to spell their name all the time (and get eye rolls behind their back).
I think what you are saying (and many do, including myself in terms of my long list) about choosing an uncommon/semi-uncommon yet legit and correctly spelled name is a great thing to do, as long as you love the name, is a great thing to do.