Personally I believe that people are using BMS simply because of ease of use. They want the single plug and charge solution, instead of plugging 2 cords and going through balance charging. It’s also safer in terms of protecting the batteries from shorts and low voltage. Hence I don’t think you really really need one.
100A continuous is way too much. VESC only draws peak 60A. Tested with multimeter, motor 200KV’ish only draw about 5 - 15A peaking at 20A tops on relatively flat ground (I weight 65kg). You will drain your battery super fast if you ever draw 100A and currently not much shady cheap chinese ESC that can handle 100A constant while pulling dead weight over kilometers of distance.
The reason i switch to li ion because of less risk in getting my entire build burned down due to bad lipo. Lipo has really descent -to- short charge cycle even though they have higher energy density per pack. I believe big lipo packs are also rejected by air ports and air carriers because of safety reasons.
If you’re not in a rush, wait for that graphene lipo packs are abit cheaper. If you have the money then try get one Since I believe not getting a BMS is because it’s too hard to install or getting SPACE cel are too expensive, then it’s better to just stay with lipo and get new one if it’s shows bad symptoms.