Usually in OLTP environment like EBS Applications, tables are often get fragmented due to multiple DML activities that happens.Fragmented tables cause queries on those tables to slow down. It is very important to de-fragment this table and to reclaim the fragmented space from these objects.
For EBS we have also seen that usually gathered statistics, indexing and proper SQL tuning is plenty to improve and maintain acceptable performance but sometime it is required to reorg the table.
One primary cause of fragmentation is that when you run delete command on the tables it delete the rows but doesn’t frees up the memory and also do not changes the high water mark.