Schema binding seems to not be enforced for view doing temporal query
I think one thing in this case must be considered: your view is not referencing the temporal table directly, it is using a feature from SQL Server to get data that is stored on a different table (the history table).
The graph from the doc How do I query temporal data shows how you get the data from a temporal table:

If the picture shows the real data flow, your query doesn't directly &quot;touch&quot; the history table. Therefore, your view with the history data is not exactly dependent on the history table.
Of course the following is not the appropriate way of manipulate temporal data, but I think it helps to exemplify my point:
CREATE VIEW [vwTemporalTest_doingTemporalQuery2]
WITH SCHEMABINDING
    AS SELECT [Id], [Description], [period_start], [period_end] 
       FROM [dbo].[TemporalTestHistory];
GO

This view is directly referencing the TemporalTestHistory table and when you try to alter the history table as you did before, it throws the error you expected. Also, this view appears on the INFORMATION_SCHEMA.VIEW_COLUMN_USAGE.

Important remarks
Under the Important remarks of the Creating a system-versioned temporal table you can see that:


The history table must always be schema-aligned with the current or    temporal table, in terms of number of columns, column names, ordering
and data types.


And the Important remarks section of the Changing the schema of a system-versioned temporal table doc says:


Specified schema change is propagated to history table appropriately    (depending on type of change).


From those remarks it seems we're not supposed to do changes directly on the history table as a good practice.
About the INFORMATION_SCHEMA.VIEW_COLUMN_USAGE not showing any info regarding that view I couldn't find any explanation. By the way, this is the conclusion I could get from tests and reading the docs I mentioned and I posted it as it might help to get to a more accurate answer (maybe it will be considered as a bug like you mentioned).