There are apps that are common and people do install it eventually (e.g. Gmail/facebook/Whatsapp). It make sense to install it by default and make it available for people to start using right away on their new phone. However there are ton of other apps that mobile manufactures pre-install and that is annoying to users.
As a user you may never use these pre-loaded apps. Just an example, I got Samsung S4 (from phone service provider) and it came with 80 odd apps, out of that I never ever used 40 apps! That's huge set of apps pre-loaded. It may vary based on which phone you buy, however its obvious that new mobiles does comes with good number of pre-loaded apps - which you never will use!
Pre-installed apps can run in background and has all permissions:
Even though you never use all those pre-installed app, they are still there and running behind the scene. Each app has permission granted to them and can read/write your SD card, has network access, can intercept phone calls/sms and do much more. Result - Privacy/security issue in addition to battery drain which you never notice.
User can't uninstall pre-installed apps:
Problem with these pre-installed apps is that user cannot remove them. They are installed in system space/partition and thus locked by android/mobile vendor. Users cannot uninstall it. You are stuck with those 40+ odd apps!
You can remove those apps if you root your phone. However rooting is not recommended and not easy way for anyone to try out. Rooting is a process of gaining admin access to your phone and with that access you can do all things on your phone. There are ways to root your phone and you can find steps on google to do so. However its not straightforward and it voids your phone warranty.
Best way to solve this is to disable pre-install apps!
Navigate to Settings > Application Manager and open up apps that you don't not use. Mark them as disabled and here you go. These apps will not run or update any more. Will not carryout any function and will not read/write data or use your internet. Result - a safe phone to use.
Basic security concept used here is - less the number of apps, less is the security risk. Same concept applies to your new laptop/tablet too.
Its not that user don't have option about pre-installed apps. You do - go ahead and review apps that you don't use and disable them.
Warning: Do make sure you are not disabling any system apps. Do try to run the app that you plan to disable and check if its not a android-system app.
Advantage you get -
- Better security / privacy by keeping minimal apps running
- Improved battery performance
Do comment below and I will be glad to answer it.