I think a lot of the benefit of having an external drive is having a backup. I have 3TB internal and that's completely full. Of course not all of that 3TB is stuff I absolutely need a backup of but a good portion of it would be nice.
That's so last decade 
The internet is for backups.
I'll back up my stuff on the internet when hell freezes over. You know who I trust with my personal files and information? NO ONE, except me. Backing up at home is easy. Say you have a 1TB data drive in your PC (you should at least mirror this as well)....You buy a hot swap bay for next to nothing, then buy 2 1TB drives, also cheap. You setup an rsync job to copy all the files over to the drive in the bay every night. Take that drive to work, or some place not at your house. Then, put the second one in the bay and continue the backup process. When enough changes bring that one off site and bring the first one back. Cheap, easy, effective. You could get fancier, but I haven't found a need to yet.
Call me old fashioned, but I hate "The Cloud".
I am right there with you on this one. if you back up to the cloud you are basically giving away any advantage you might have:
1. a salesman backing up his list of top customers would be giving them away.
2. if you,re writing a song you're basically sharing it with everyone.
3. if you're a writing a lecture or thesis you're basically sharing it with everyone.
in my mind these are the big issues - this is not about porn (although there is that) or even you deep dark secrets - this about IP : your IP.
granted, if you have no intellect then this is more likely than not a moot point, but still ..., don't ever let people reduce this conversation to something like, "well if you're not doing anything bad you have nothing to hide."
that makes it sound like the only utility privacy can provide is its abilty to conceal misdeeds you may or may not have performed.
that's a false dilemma.of course it can do that but privacy can also provide another utility: it can protect your property from theft.
tldr;
don't backup to the cloud