Table with data but not segment

I would like to clarify or confirm. I can query (user_tables union user_indexes) minus user_segments and see about 4 tables and 9 indexes. 7 turn out to be normal and 2 are IOT - TOP indexes.

I guess the 3 tables with 0 rows and all the indexes that go with them might not have a segment?

There is one table with and IOT - TOP index with 100000 rows. Two indexes go with this table, one of them is IOT - TOP, the other normal.

Even and Index has a segment, why would I not have a segment for this(ese) table(s) or Indexes?

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