I just register an account on Lotus a few days ago, so this is my answer:
Lotus (and by extension, Gapo, just in case you want to bash them together) is a new social network made by Vietnamese for Vietnamese. Because it is new (very new, less than 6 months old), I refrain from commenting anything. I prefer a “wait and see” approach to see how it goes
Showing the ID is “optional”. And now, they are not asking you for the ID, I just check the “personal detail” tab on my Lotus, and they are lines for
Your name (to “show” on Lotus)
Your nickname
Gender (Male and Female - I expect so-call LGBTQI… right activists in-bound)
Your own self-description
Job
Place of work
School/University
Place of resident
Email
Phone
Date of birth
URL Facebook or Instagram
URL Telegram
So, there is no such thing as “asking for ID number”. Either you are using a “recently updated” version (I recall there are 2 or 3 updates since I install the program), or you are simply lying.