Hello

Many student now a days go for dual degree let us see the advantage and disadvantage :

Advantage:

Better salary

Better chances of placement due to extra one year .

Internship:  you can go for more internship and many experience.

Better projects : more time for more project and get a good overlook of industry work.

Disadvantage:

Waste of 1 year if you don't  do anything

Many people leave in 3 rd or 4th year .

Not  good for mba students

So basically go for which you are interested in .its not about 1 more year but it is actually about your career and future

Feel free to ask

Good Luck...