Reddit, Facebook, Paypal, Amazon are all the only sites this computer connects to.
The attack vector of malicious ads on these sites are the largest attack vector - which is nearly abysmally small since Chrome is a better sandbox than windows is.
Aside from 0-days, which are basically/practically out of scope, the only thing to worry of is automated scans and 3 letter agencies.
I am behind a NAT, and the 3 letter agencies are inescapable - but a defense of "my computer is old and insecure" may retro-actively be the only plausible deniability that the "layman" such as myself can muster.
Hypothetically. Similar to having an open wifi network for the sole purpose of muddying the waters and adding noise to a signal.