Generally speaking it’s better to have a single power source to train and race on.
You are better off being in a situation where your training zones match up with your outdoor zones, rather than knowing that they are different, if you use the power meter at all for pacing, eg breakaways, hill climbs etc.
If you only ever ride outdoors by feel, and passively collect power data, then go ahead and use the neo as the power source, but if you use the power meter outside, just use the same device for both to ensure you are comparing apples to apples.