At any rate, I think having unsigned binaries that are not notarized introduces additional hoops for non-expert users, since macOS requires signed bundles by default (which is a good thing!).
To come at it from another direction, why is it your users' responsibility to work around your own cheapness/laziness? Just front the $100 and sign your damn app, especially if you're making money with it.
Moreover, signatures and notarization are there for a reason. Code signing makes it more likely that the bundle was not tampered with. Apple can revoke the certificate if the developer key leaked. Notarization will catch at least some forms of malware.
I refuse to run unsigned code (with one exception), because it decreases security significantly. There have also been severe incidents in the past with unsigned code, e.g.:
https://blog.malwarebytes.com/threat-analysis/mac-threat-ana...