Advantage and disavantage of malware maintenance

Well, advantages are,

it keeps your computer secure
less likely to get a virus or malware
can keep your passwords and bank details safe if entered online (if you use software like avast)

disadvantages are

they can be expensive to buy
can use a lot of room on your pc
sometimes cant fully remove a virus and just puts it into a virus locker or chest
they can sometimes be almost impossible to remove and act like a virus themselves (norton, avg etc)