This seems to be a reasonable situation to define limits to what a law abiding person needs for personal use.
Seriously? I hope you are the last one to say it. Reading between the lines of your quote above, it would appear that you think it might be reasonable to outlaw access to this technology, solely because you can't think of a legal use for it.
As others have posted, there are certainly legal usages. I can think of others, but that is besides the point. The whole idea of limiting something because it might be used for illegal purposes is ridiculous.
Regardless of the "legal" ideas proposed, sometimes new technology leads to new ideas, i.e. as storage costs go down and capacities go up, new ways of using storage may evolve. One (possibly half-baked) idea I can think of is crowd sourced, highly redundant, "free" backup storage.
First, the summary above says that Seagate will produce a 60 Tb drive by 2016. That is not true. Seagate has said they will produce a drive with "up to" 60 Tb of capacity (30-60 TB) by the end of the decade. This is based on the theoretical limits of HAMR technology, which are projected to be in the 5-10 Tbits/sq. inch. range. Current 4TB drives are made with platters that have a density of around 650 Gbits/sq. in., so the math works (10Tb/.65Tb is approximately 15x).
The other part of the article is talking about what the maximum density is likely to be over the timeframe from now to 2016 using PMR technology and transitioning to something new like HAMR. PMR technology will top out at about 1Tbit/sq. inch, so anything over that will require something new like HAMR. that underlying article quotes 1.8 Tbit/sq. in in 2016, which may not be out of line with 5-10 Tbit/sq. in. by 2020 as a new technology like HAMR comes online.