Of course your particular use case may vary, but I use TOR and Orbot if I am trying to mask IP location or a dedicated VPN.  The way Opera is doing that through just a couple of their own servers in a couple of locations would make it trivial for anyone who had access to their servers to provide a trail leading back to you, that browser company and VPN service is owned by a private company.  Even someone who did not have their cooperation but had access to nearby routers could work out where you came from.  If you are just trying to hide your location from a website you are trying to visit to watch videos or something no problem, but if you are actually trying to keep your IP private this is not the best method and this kind of proxy is actually leaking a lot more data about you than it is hiding.

What opera is offering is not really a VPN, it is a proxy with a lot of marketing hype, and they are an ad distribution network which is offering that service in order to catalog your usage data for marketing purposes, and anyone who is doing that is creating a record of who you are where you came from and what you are looking at, which is usually what you are trying to avoid by using a VPN.

https://www.helpnetsecurity.com/2016/04/22/opera-browser-vpn-proxy/