I've made this argument before - for some (at least me), having lines makes it harder, not easier. Unlined and side dots gives you a rough visual reference, so you have to really rely on your ears and practice/muscle memory to nail intonation. For me, with a lined neck my brain gets a short-circuit between chasing the lines for intonation and the reality that on a fretted bass I play behind the lines, so my eyes say "fretted" but my ears don't.
Not everyone is wired as oddly as me. But I have a tough time playing in tune on a lined neck. I find unlined much easier. I also have been playing unlined for a lot of years so part of that is what I'm used to.