Part #2
Reputable “paid” commercial VPN services have no vested interest in your internet traffic beyond statutory obligations imposed by the authorities in whose territory in which they operate. Again, from a regulatory a technical perspective, this is no different to your ISP or mobile phone operator. Reputable commercial VPN services are fully and profitably monetised by service subscriptions.
Free or “low cost” VPN operators are funded differently. Clearly, these VPN operators have cost overheads that must be fully funded; such services are often funded through commercial advertising served via the VPN connection, or traffic analysis and data mining - this data being sold-on to other interested parties. Dishonest VPN operators may attract business with express intention of misusing your data - or to facilitate criminal activity.
Looking now areas where commercial VPN provides useful threat mitigation…
Assuming that your home wired/WiFi network is secure - and that other network devices using the network are trusted - use of a VPN within your local network offers no significant benefit. By contrast, public WIFi networks (such as Airports and Hotels) are high risk; other users of these networks can access and manipulate your network traffic - and it is here that a commercial VPN provides useful protection. Here, when using a VPN, all your traffic is fully protected from actors over the high-risk elements of the network path - between your client device and the VPN Gateway.
So, addressing your numbered points…
1) Little benefit. Your home network is presumably trusted; traffic from the VPN Gateway to your Bank benefits only from protocol encryption.
2) Websites to which you direct traffic will, by definition, see all data that is directed to the website.
3) VPN connection will provide privacy over the path that is protected by the VPN link - up to to the VPN Gateway. You might strategically choose the country in which the VPN Gateway is located - being mindful of reciprocal intelligence agreements between governments (e.g., “Five Eyes”). In most cases, effective protection from Nation State interest is an impractical goal.
4) VPN provides effective and useful protection from local threat actors likely present on untrusted network segments - such as schools, airports, hotels etc.
5) You may be retired - and whilst most most law-abiding individuals have nothing to hide, you have everything to protect.