I liken writing SQL vs using designer tools to driving a standard transmission vs an automated transmission. With a standard, you have more control over how the vehicle operates, and likewise, when you write your own SQL rather than have some designer write it for you, you have more control over what the DDL is doing. Sure, you can have a designer do it for you and then tweak it, but are you really looking at all the automated ~decisions~ the designer is making for you, or are you saying "well, the designer put it there, so it must be ok" and ignoring it. If the latter, that, to me, shows a lack of curiosity and ultimately a lack of understanding. Even if you make sure to understand every part of the auto-generated SQL, I argue that this still takes longer. When you need to change a check constraint, I had a dev spend 30 mins trying to figure out how to get the designer to change it and then generate the SQL, and when he had trouble with this he came to me. I wrote the ALTER stmt in less than 2 mins. I don't mean to be too harsh on those who "grew up" doing it that way, but you exercise and strengthen your brain muscles more effectively when you make an effort to figure out how to write the stmt without a GUI to help.
p.s. I've been coding long enough that yes, I wrote my first HTML in notepad as there weren't many IDEs back in the early 90s. While I agree that having IDEs are helpful, I don't think I would have learned nearly as much if I had not had that original experience of having to figure it all out by trial and error.