Well, as somebody mentioned above, with any software you don't actually own it, but rather you have a license to use it. Hence the reason they can stipulate how many installs you can use, etc.
As far as the subscription goes, you have to evaluate your situation to make the call. For example, there was a time when I needed the Office Professional products on 2 computers. My desktop and my wife's laptop.. For a 100% legit license from Microsoft, the cost was in the $450 range, PER COPY. So, at 2 copies...I was looking at nearly $900. Ouch.
Instead, I went with Office365. For $99 a year, I was able to install on my wife's laptop, and my desktop. So, on day 1 I had 1/9 the total investment into things, and I got 1TB of OneDrive space and wife got 1TB of OneDrive space. We were already considering upgrading our DropBox membership to get more dropbox space and that was $119 a year at the time for 1TB. So, for less than we would have paid for Dropbox alone for 1TB, we technically got 2TB AND Microsoft Office to boot.
I'm now about 5 years into things, so I have spent ($99.99 x 5) 499.95. Still less than I would have spent above had I bought 2 full standalone copies on day 1. And tomorrow I can cancel my subscription since I don't actually have a need for Outlook any more at home nor Access. I could go without Microsoft office pretty easily. Unfortunately with the stand alone, I would have been out that $900. But I'm keeping Office 365 regardless because we are all making use of our 1TB of one drive space that we get with our accounts. That alone is worth $99 a year to me.
All in all, I've felt the Office 365 a no-brainer for me. We have it installed on lots of devices. (3 desktops, 3 laptops (2 of which are Macs). I've given my dad one of my seats (so he gets Office and 1TB of OneDrive). I'm always on the latest version without having to buy another copy. I don't have to take any chances on low cost, potentially shady keys. And I get more cloud storage space than I need.
But I can totally understand the person who just uses Word and Excel, needs 1 copy and sees no point in Cloud storage. They would be better off with 1 copy of Office Home and Student.....It's not even a debate.