Summary of thoughts on courses in PhD vs learning on job:
The ML and Data Engineering (DE) pieces are the main areas I see as needed for career advancement. Theory is helpful info to know/makes you better at the ML piece but I don't think is critical for application of DS in industry / stuff worth going back for a PhD for.
The DE stuff are things I get SOME exposure to at work and what I don't currently get exposure to I believe I can learn on my own. my general feeling is that DS people tend to more "learn on the job" with the DE side if they are a data scientist. Worth noting however that UVA classes in DE + work experience in DE >>> just work experience / self learning. Also worth noting that while there is one very helpful mentor at SA for ML OPS (named David) in general, the ML Ops space is somewhere SA REALLY needs to improve. This is pretty common across smaller, private tech companies. So far our improvement here has been slow and I don't expect it to get better / be a priority to fix until we are a public company (at least years from now).
ML:
The first 2 courses (intro and Methods/applications) are really just what is call "statistical learning" and is the version of machine learning that walked so "Deep learning" (the 3rd and 4th courses) could run. This is the type of work I do on a daily basis at work and feel extremely comfortable with. Note that most industry level machine learning / Data science / AI using in industry today is what is covered in these first 2 classes. as more of the workforce learns how to code / work with data in the next decade, I don't believe this skill will be as much of a differentiator as it is now (however experience using this to solve problems / applying it to specific domains will always be valuable aka the experience I am currently getting at SA).
The third and forth courses are what I would want to be doing long term. deep learning is what powers pretty much anything AI that you will see in the news. Self driving cars, chatGPT, any kind of autonomous system or project that requires decision making is likely done by a deep learning model. things like chatGPT / self driving cars are the make front page news applications I tend to use as a quick example, but there are a massive number of real world import problems in business that dont make headlines but are only going to be solved with smart applications of RL/Deep learning (ex. like teaching computers to use their hardware more efficiently during ML work, how power grids can make autonomous decisions to make themselves more durable, improving allocation / sharing of resources during logistical transportation In my opinion, this is the area of expertise that will continue to be valuable for the full duration of my career. I have taken some classes in this but I am fully NOT qualified atm to get a job where I would get to apply this. From a limited amount of research, even if I take classes on my own time/do projects it is possible but pretty difficult to find a job a where I could demonstrate my intro level understanding of deep learning while apply and then learn on the job. Also, while I love learning /apply this, it is genuinely complicated and I would probably be better at using it long term if learning / researching deep learning with genuine experts at a university vs "figure it out as you go" in industry