Difference between SY-TABIX and SY-INDEX? Where it is used? | SAP ABAP

SY-TABIX - Current line of an internal table. SY-TABIX is set by the statements below, but only for index tables.
* APPEND sets SY-TABIX to the index of the last line of the table, that is, it contains the overall number of entries in the table.
* COLLECT sets SY-TABIX to the index of the existing or inserted line in the table. If the table has the type HASHED TABLE, SY-TABIX is set to 0.
* LOOP AT sets SY-TABIX to the index of the current line at the beginning of each loop lass. At the end of the loop, SY-TABIX is reset to the value that it had before entering the loop. It is set to 0 if the table has the type HASHED TABLE.
* READ TABLE sets SY-TABIX to the index of the table line read. If you use a binary search, and the system does not find a line, SY-TABIX contains the total number of lines, or one more than the total number of lines. SY-INDEX is undefined if a linear search fails to return an entry.
* SEARCH FOR sets SY-TABIX to the index of the table line in which the search string is found.
SY_INDEX - In a DO or WHILE loop, SY-INDEX contains the number of loop passes including the current pass.