There is nothing wrong with construction lines. Andrew Lumis the famous illustrator wrote books on his method of drawing dubbed “the lumis method” which goes into constructing a head/face or hands from basic shapes and working your way up to the full drawing. In his life and his work he used his own method all the time to draw faces and people.

While I understand not wanting to rely on them anymore for drawing anything your goal should be to intuitively understand the process your using without thought which only comes from practice.

It isn’t bad to use them at all. It’s no different than laying out a sketch before you start painting.

If you don’t want to use them, that’s fine, enough practice will get you past a necessity level for sure, but I consider that to be a personal preference. You’re no less an artist for using them than you would be for sharpening a pencil. Construction lines are a tool. A damn handy one at that.

They allow you to build your image in proportion before committing details. That makes the overall process faster and more controlled. There’s a reason a lot of comic artists use them when doing pencils. You lay out the construction lines and you have the scene all mapped out, a way to be able to do details without losing track of the big picture when you’re on a schedule.

There’s really no wrong way to draw. You can find proponents of all different kinds of techniques, with and without guides.

Ultimately, all that matters is what works for you.