What is the point of morning sickness in pregnancy?

This is an unconventional post on my end. It honestly feels too personal to talk about, but my goodness, the morning sickness of this pregnancy has left me in shambles, as per usual. This isn't my first rodeo, it's my third. The thing is though, why? Why does this happen? What good does this do if it just makes me anemic and nutrient deficient? I end up avoiding most nutritious foods because the mere idea of them I cannot stomach. I can't even eat eggs. This recent week has left me eating one specific craving as a safe food, the rest is basically filler so that I don't pass out. But the nausea keeps me avoiding strong smells, heat, any uncomfortable situation that makes me feel worse than I already do. I still breastfeed my youngest, and so I need any calories that I can get, but my energy has tanked these recent weeks because my only source of calories has been easily digestible foods such as pasta, pizza, cheese (which I shouldn't even be eating) crackers, and fruit. Cold ginger…