How essential is using a weightbearing nail? How big a difference does it make?

My understanding is that with it you can walk virtually immediately after the surgery (not normally of course), so you can get started with PT immediately, and you experience less muscular atrophy so recovery is faster right? Plus it's psychologically easier cause your mobility is far less limited (no wheelchair or crutches). What other benefits does it offer and how essential is it in making the whole LL process easier physically and mentally? Is money the only reason why someone wouldn't use it for their LL or are there other concerns or limitations?

Bump

None of the nail in the market right now is full weight bearing. You will still need to use clutches to walk

With non-weight bearing options, patients are essentially fully immobilised during the lengthening period. This delays functional rehabilitation and exacerbates muscle atrophy. Weight bearing also accelerates bone regenerate (doi: 10.5005/jp-journals-10080-1572). You can find studies strongly supporting early rehabilitation in almost all fields of medicine, particularly orthopaedics (eg hip replacement).

However, as JustineCollins correctly points out
Even with "weight bearing" nails (eg BetzBone, G-nail), the patient will/should use crutches when walking – at least outside.

First, for stability and safety: falling or putting too much pressure (could be one wrong step) on a weight bearing nail will break/bend it.

Second, walking with crutches helps the patient regain a normal gait pattern. To appreciate this, you should know that after implantation, and prior to consolidation, the nail will be moving discretely in the intramedullary canal during ambulation. Enough movement that it is sensed by the body. This is normal. The patient will spontaneously attempt to compensate for this with altered gait (eg penguin gait). Crutches helps avoid/correct this.

M

weightbearing nail is better in general