Answer and Explanation:
1) The three important features are:
Graphical representation of data-Data can be represented in the form of pie char,bar char,etc
Data Validation-Particular data type can be assigned to a column so that only that data type can be entered such as int,float and character
Aggregate Functions can be used such as count,sum,average,max,min,etc
2)Professions which require excel are:
Auditor-These people are brought into the frame of a accounting during a specific event or generally quarterly or annual
Accountant-Accountants require the excel very much for maintaining records and perform calculations quickly
Sales Manager-He may need to calculate the growth rate of the company in terms of sales for which he can use excel
3)Yes there are some tasks of excel which can be done in word or power-point.If used just to enter data in tabular format then word or power-point can be used to represent the data in tabular format.
Benefits:
Word and PowerPoint offer better multimedia support than excel
PowerPoint offers better chart choices than excel
Limitations
if there are any mathematical calculations then it is not possible in word or PowerPoint