Magandang question din yan. What application will be used to play movies.
After stopping production, Apple supports devices for at least 5 years with service parts. The Late 2014 model is still being sold, so I guess it is still worth at least 5 years more before Apple deems the hardware obsolete.
Apple provides security updates to each OS version for a span of just 3 years (that means an OS upgrade is required within that period if you want to keep your system secure). Fortunately the Late 2014 Mac Mini is almost guaranteed for upgrades for at least 2 years more (to complete the 5 year support period), though it's likely to get it for a year or two longer than that.
Microsoft provides extended support for their operating systems for at least 10 years. This is why Vista is still supported and updated (until next year). Windows 7/8/8.1 users have the same 10 year window, but those who availed of the free Windows 10 upgrade will get guaranteed support until 2026 (that is 17 years of support for original Windows 7 users).
This is a huge reason why Microsoft is the dominant OS supplier for business computers. Despite its poor security image (since most exploits target the most popular OS), Microsoft has been among the most diligent in patching vulnerabilities. By providing a long support window, large organizations are not pressured to continuously upgrade and this allows for less fragmentation within the organization (same OS can be ran across different generation machines, making software validation and maintenance so much easier).
I prefer Windows because it gives me hardware flexibility (not a locked-in ecosystem) and it remains fairly secure software-wise until the death of the hardware (most computers don't last 10 years). Windows 10 is officially backwards compatible with processors dating back to 1999 (and some are able to squeeze even older machines to run on it); that is theoretically leasing those machines secure life of 27 years. Apple makes pretty durable hardware, but my opinion is that they go to waste after the support period (granted this doesn't affect most of its target users).