Ok, i did a bit of research way back and what i came up with is the reason why you should avoid using neem oil and use neemazal instead (or any other trusted neemazal formula).
The most important reason is the aflatoxin which most neem oil has. That is what makes people sick when they ingest the stuff. No matter how organic it is and how flashy their packaging is, aflatoxin is a real concern with neem oil. However water based extraction of azadirachtin compounds such as neemazal technical and organic, aflatoxin free vegetable oil suspension of the same stuff neemazal t/s are safer in that aspect.
Secondly neemazal doesn’t leave an after taste unlike neem oil and the vegetable oil used in neemazal t/s is more easily broken down compared to the neem oil. Thus it leaves less residue and doesn’t clog up the stomas which happens with straight up neem oil. Also since these are more concentrated than neem oil, you require less to get the same effect and that contributes to it being gentler to the plant. So thats what i found out about the differences between neem oil and neemazal.
With that being said, neem takes time. Azadirachtin doesn’t kill straight away, it inhibits feeding and reproduction in pests but it takes time. Tho the vegetable oil in neemazal or neem oil itself will suffocate the pests, the ones you missed will not die immediately just by eating the plant. Also i’m not sure how effective it is for caterpillars or slugs etc.
Additionally with neemazal a 7 day waiting period in average is suggested if i’m not mistaken but i never apply pesticides once its flowering. Tho indoors its easier to keep it pest free. But azadirachtin is not toxic to humans and its not recognized as a carcinogen or anything so thats kinda your call.
Hope this was helpful.