I wouldn't say it's necessarily weird, and I'd never call it unprofessional, but I have also been using CI of some shape or form since I entered the industry in the '00s. From home brewed scripts that were cobbled together internally, to CI servers on-prem, to CI servers in the cloud, and now back to on-prem. At work, I am literally in the middle of a massive migration of my teams multiple CI servers. We have dozens, sometimes hundreds of jobs kicked off on a daily basis + at least 2 dozen nightlies. Without CI, our team would be dead in the water.
maybe I just get hung up on the "professional" aspect. I'd say for the most part I've always had some form of testing, just nothing that ever fit neatly into something like gitlab or github's CI/CD products.
