When I was first learning Powershell, it happened to coincide with a data center move. We were going to physically move our data center between builds. Loads of planning went into it. When it came time to do the move, it was announced, late, that before the move started, as we did each set of machines, they wanted to add an additional backup (not a bad idea). We had already divided the work into shifts. A team would come in, move a set of machines, ensure it was all good, then hand off to the next team and the next set of machines. I was on the second shift. The first shift person had to run backups of all databases on a set of servers. Now, we had a good t-sql script to backup all the databases on a given server (with include/exclude lists, all the bells & whistles you can think of) and it was installed on every instance by default. All set right? Well, yes & no. Now, we needed a way to manually fire it off on a set list of servers. First person, got the list of servers, opened SSMS, connected to the list of servers in a set of query windows, and walked through the set of 12-15 query windows, running the script, and then scrolled between them, one a time, until they were all done. Then he gathered all the results by copying & pasting, and sent that out. All told, it took him about 4 hours to do everything. When I came on, he explained this to me. After rolling my eyes, I sat down, spent about 45 minutes writing a powershell script. I ran it. It took less than an hour and I had the backups done and the output report. I then handed that script off to the next shifts who all completed their work in less than an hour. When we were done, we never used that script ever again, because it solved a rather unique problem that we never replicated.
It's not that anything I did was special. In fact, I'm positive the script was crap and could have been written in a much better, more efficient manner. The key difference was, one person chose to do everything manually, another spotted an opportunity to automate stuff. Be the person that automates stuff. I would argue that knowing Powershell AND SQL Server internals, etc., are both needed to be an effective DBA.