Here's a different perspective - it depends.
I'm a high school coach w/ every kind of ski on kids feet from thrift store bought, donated, beat up by kids to top end new. I've "refreshed" the bases of these using several techniques including steel scraping & modest price stone grinding. There is no question that I can prepare a better base w/ a steel scraper & hand structure tools than several of the low cost grinds I've seen. But I can't beat a top end grind for our usually wet snow conditions. The bases need more structure than I can put on by hand. And I'd never steel scraped a top end ski except to repair a small section.
It would be a different story if you ski mostly on cold dry snow. Hand scraping & modest hand structuring could work fine for skis that are rarely raced.
But here's the other part of the story. The real skill & time needed for steel scraping is in sharpening the scraper. You will get best results when you have a razor sharp slight burr on the edge of the scraper. It takes a couple hours of practice sharpening & then deburring & starting again to learn how to get a proper edge. I've built a simple wooden jig for scraper sharpening & bought high-end wet carbide sand paper to use for this. Then you will need a couple hand structure tools like the Swix or Toko that are appropriate for your snow.
So ether way, you are going to spend some $$ & if you DIY your bases, you'll also spend a lot of your time.
Finding the right balance between the cost & time of ski prep & the type of skiing you do is not simple. It takes time to find the simplest, least costly & least time consuming approach that still allows you to have a great day skiing.
Best of luck!