If you take a beginner cooking course you'd normally learn bechamel very early on - it's the base of so many great meals. I mean, it's a white roux and milk. While I was half joking in my previous comment I'd expect the way an app would work is to start with easier meals (maybe a mac & cheese, as this uses a bechamel as the base of the cheese sauce) rather than adapt more difficult meals for simplicity. I thought I'd get away with this joke because the original commenter seems to know his stuff around the kitchen and would appreciate a classic comment about Italians and their sometimes intense beliefs in sticking to traditional cooking :P
Okay I concede this is Western, yes. But they're used all over, even if they get slightly adapted over time to the local area. I was learning Creole cooking the other month making a gumbo and it starts very similar to the espagnole mother sauce (a dark roux) with a modified sofrito (red peppers instead of carrots).
And also, if you look at the best cooking schools in the US such as Auguste Escoffier they also start with lessons on Italian and French cooking because of its influence on so many other cuisines.
This stuff is like learning variables and functions in programming - they're just core essentials and if you want to learn cooking, as you'd expect from an app-based course on cooking, you'd expect these to be early topics :)
Of course we're getting off track here because I was originally just joking with the OP as mentioned in another comment and seen in their reply. The Italians are stereotypically very protective of traditional cooking recipes (watch almost any Italian chef on youtube make a dish).
They are core essentials for the Western cooking tradition codified by Escoffier. The Indic tradition is different (and North India is quite different from South). There are at least four major groups of African traditions. I am being profoundly ignorant by referring to the Asian tradition - Northern Chinese is wheat-centered and Southern is rice-centered, and Thai flavors are quire different from Viet not to mention Malay...z
And none of them use the mother sauces except the Western tradition.
Humans have great diversity in food, and that is wonderful.
Not those mother sauces, and not by that particular name, but Indian cuisines do have the same "variations on a theme" structure.
A lot of North Indian dishes start with a base of tomato, onions, ginger, and garlic, to which various things are subsequently added. I think you could call that a "mother sauce", and people occasionally do: https://food52.com/blog/19216-does-indian-cuisine-have-mothe...
I'm not Italian, so I don't care as much...
Also, as the original comment mentioned, this is supposed to have different degrees of how easy/flexible/practical it is