I use Malwarebytes on my MacBook Air. I did not pay for premium so I do not get realtime protection. That's fine, I don't feel like I need to give up CPU cycles for that.
I have been using Macs since the early Nineties and my systems have not had any malware. If I recall correctly, Macs have not had any viruses (following the technical definition of 'computer virus') at all.
Admittedly some people have more promiscuous computer using habits than me. A lot of this comes from not using content blockers. Using content blocking technology is unassailable if you do it primarily for security reasons.
This thread is getting silly. Whether Windows-like virus for Mac exists or not is besides the point.
If you are careless and click "OK" and enter admin user password to allow some random app to be installed (e.g., fake app updater), your Mac can be infected with adware, trojan horse, or ransomware. And some MS Office files can be infected, which cause smaller damage, but damage nevertheless.
If you fall into these risks, then it's certainly advisable to have some protection.
Aforementioned Malwarebytes is probably the least intrusive, although it is also known to be protect less (but certainly good enough for most).
Sophos is more robust solution, but it tends to be more resource hungry than Malwarebytes.
P.S. I personally recommend updating security updates frequently, not lower default security settings, and avoid letting some random app to ask for admin password. And keep Malwarebytes in free mode for routine system scanning or cleanup prior to installing an app you downloaded from the website.