Part of an undertaking this big is securing funding and political/social support. Being a bit "trendy" helps with those.
The whole system appears to rely on a trusted group certifying the [probable] authenticity of an individual's records and Rohingya refugee status, in which case you might as well let them host it on a well-backed up regular database...
A regular database has no way to make it infeasible to insert fake old records. Sure, you can publish checkpoints. But that doesn't work so well when you're up against a government that wants to erase your entire ethnicity.
(In practice, I think the Myanmar government's strategy would simply be to disregard the database rather than to attack it anyway, on the basis the local prejudice against the Rohingya isn't based around their numbers or individual identities but the claim that they are actually Bangladeshi illegal immigrants lying about Myanmar ancestry and land)
And yeah, a government would certainly try to ignore facts it didn't like.