I did some reading online about date types in MS SQL Server, and I no longer wonder why 1C still clings to its date offset. People describe a whole bundle of DATETIME2 problems:

1. You can’t do basic date arithmetic. Want to subtract two dates or add a day? You’ll need a workaround.
2. Standard functions still return good old DATETIME, DATEADD for example. If you store your data as DATETIME2, you have to convert it.
3. Fields of this type don’t index well, since each DATETIME2 value is stored backwards, time first, date second. So the DBMS gets its row count estimate wrong and comes up with a bad execution plan.

You can read more on Towards Data Science or, for example, SQL Server Central.