To me it sounds just like what it is: an informal childhood nickname for a child who can't pronounce her full name of
Elizabeth yet.
Using it will also make people think you are a super-fan of the royal family (think
Diana bedspread,
Harry cup,
Meghan t-shirt etc.).
It is usable but it sounds like someone who is mumbling trying to say
Elizabeth and I prefer
Lily or
Elsa or pretty much anything else.
Please rate my list:
https://www.behindthename.com/pnl/6232