If ANY of your INSERTS are rolled back then that IDENTITY will NEVER be assigned.
In a multi-user system Person-A starting to create a record, which for some reason takes a long time (e.g. blocking) then Person-B can have their record created first. Although created "later" Person-B will have the earlier IDENTITY value. So Chronological is not guaranteed either
Here's the bottom line: Don't ever build a system that assumes that IDENTITY is CONTIGUOUS ... as already said, use SEQUENCE if you need that (e.g. for an Invoice Number) - or manage the "next available number" yourself - e.g. in a NextInvoiceNUmber table - other benefits of that - you can allocate a block of numbers and you can tell a child-process what the Reserved Number(s) WILL be ahead of time.