@Eldoria
The issue lies in the suspension of disbelief. Local characters would never possess the knowledge or experience a reincarnation brings to the table.Reincarnations allows you to bring a set character at a younger age that would be possible.
However, I wish more authors would write local FMCs, princesses who grew up in a fantasy world (not reincarnations), because the conflict would feel more organic and grounded.
Note: My FMC is also a former princess of a local kingdom. You could consider it a dark version of villainess without reincarnation.