Not true. Server 2008 R2, patched around 98% of the CVE's. What windows 7 lacks is the TLS 1.3, SMBv3 or the fact that you cannot run SMB multichannel(use multiple NIC's to gather more LAN speed.
Windows 7 security holes for POS are even less, but recently PCI-DSS announced that some cryptographic updates are needed and they don't hold any responsability if something were to happen to that POS device.
In a household environment is completely up for the job
all these cardboard programmers are wrong to think that Linux is more versatile than Windows. I could instantly demolish this argument but I don't have the patience, the necessary reward and the correct place to do this. My resonance here is very limited since is a drug oriented website, not a techy savvy forum at very least. The TLS 1.3 stupidity can be fixed with a local proxy via stunnel or similar apps. Now your Win7/8.1 is fully equipped with the latest internet protocol. But there's no sense in just using 1.3 since 1.2 will work for the next 10-12yrs and online possible less, 2030ish.
What will break the protocol is the cuantic computers aka (PCQ) but other than this, you're ok
it's easy to talk if you think you own a degree and this is it but is not. Again, I dislike cardboard programmers!
I could expand tremendously but I'll officialy stop here. A last argument is this. Use whatever you like. Period