So what is the real scope of bodhicitta
It is actually a multilayered concept.
Firstly (for Mahayana) generating (what I know as) Aspiring Bodhicitta (which is a general wish to be free from samsara on the behest of all sentient beings) when one does dharma study and practice creates much more "merit" than if one does not create this desire or only created a desire to be free from samsara for oneself while/before studying and practicing.
Secondly, creating Aspiring Bodhicitta creates the karma and proclivity towards compassion so that eventually, spontaneously, one attains (what I know of) Engaging Bodhicitta this "actual" Bodhicitta IS the Bodhicitta that will be the drive, forever more, to seek liberation (to become a Buddha, not an Arhant) solely for the benefit of all sentient beings. When one actually experiences this unique mindstate, Engaging Bodhicitta, this is the mindstate that the Buddha himself experienced which propelled him forth to become a samosambuddha, who of course was able to help (at least) sentient beings (humans) in this world system. Then like how the Buddha mentioned of himself before he was liberated, after this Bodhicitta, one becomes a Bodhisattva, a person destined for buddhahood.
So in laymans terms, having a general desire to become a Buddha when you do dharma practice or study eventually will lead you a powerful internal experience where you will have true conviction (motivated by compassion for all living beings) that you will help them become liberated, by becoming a Buddha for their sake. At that point forward, you are then a Bodhisattva.
Unfortunately it seems quite a few sects of Mahayana, or even possibly all, but I am thinking specifically of Tibetan Mahayana, because of Gampompas egotistical comments based of the lotus sutra parable of the burning house, there is disdain for the "Hinayana" the "lesser path" of actual disciples of the Buddha, Arhants who are seen as not truly liberated and not free from samsara, that only a Buddha, via attaining the Engaging Bodhicitta is actually free. For them nibbana is not liberation, there is still more to do.
So one would assume that the people who put so much stock into Bodhicitta also have the intellectual delusion that only via attaining Engaging Bodhicitta and going through the 10/16 bhumi can they themselves be liberated from samsara.
Personally I feel that this entire concept was created by "lesser" men, not taught by the Buddha himself and seeing there was no Buddha around to verify these concepts, they are essentially fiction or philosophy created by possibly puttajhanna, or path sotapannas in various Buddhist countries in the past. (assuming a fruit attainer sotapanna...onwards would already know the path to liberation as they have seen the goal so would never add to or change the Buddhas teachings, creating an entire new concept)
If one scrutinises Bodhicitta in the framework of Buddhas teachings, dependant origination, 5 aggregates and 2nd noble truth specifically, it seems to me that Bodhicitta is a mistake. A virtuous desire, but a desire non the less. It seems to me that Bodhicitta is in fact bhava-taṇhā
I also do have practical experience with both types of Bodhicitta as I originally studied and practice Mahayana, just mentioning it so that you may take this as not purely academical or intellectual conclusions of the concept.
There is also a paradoxical statement in the Lotus sutra (I forget where, but possibly chapter 2) where the gist is that when one attains a high level on the bodhisattva path and understanding of emptiness one sees that there are no actual beings to have compassion for, in turn, no beings to save, negating Bodhicitta completely and in turn negating ones own "Bodhisattvahood".
The concept is blasély brushed over with "lol just have compassion for them anyway" or something in that vein.
Which for me is illogical and goes "against" the core function of what the Buddha taught being logical reality based upon the empirical evidence anyone is able to obtain through being scientific within their own mind. Essentially a belief system! Something the Mahayana is conflicted with, because of being intertwined with pagan, hindu, and colloquial belief systems.