thepianoplayer416 After watching her video, don’t think it’s a good idea to fix your fingerings according to a predetermined formula. You need to consider the phrase before & after and use the most natural fingers to connect them
Yes and no.
Scales are supposed to teach you the keys and which fingering to use. This helps you to recognize when you're playing in the key or its relative minor and still keep your correct fingers on the keys to help you when you get to crossing over/under.
For instance; if the piece is in DM and you're in a passage which is using the natural Bm scale for that phrase, then you're still going to want to use the correct scale fingering when you're in the Bm phrase. If you don't do it this way you're going to end up twisting your fingers or having to jump in places you shouldn't be and that interrupts the flow. Scales teach you which fingers go where depending on the key signature.
Big jumps need you to land on the correct finger too so that the subsequent notes fall under your fingers properly. This again is the result of knowing the scales and which fingers go where.
And please take the above with a grain of salt because it was written by the guy who doesn't really understand theory. (And who is actually amazed that he wrote it and understands what he's trying to say even if said poorly.) However, in the end it's about the interplay between biomechanics and the keyboard. Your hands only move certain ways. If your fingers aren't oriented correctly on the keys you're going to have issues with time and fluidly.
Using alternative fingering is for those times when your physical limitations won't allow you to use the "correct" finger. Those who can't stretch far enough, or who have poor flexibility or fat fingers that don't fit between the black keys often need to find a work around for that particular part before reverting back to "proper" finger technique. However, that's the exception not the rule.