The main issue with using LFP instead of Li-ion for ebikes is weight.
Li-ion 21700 5000mAH 3.6V 18WH, weighs 68g
LFP 32700 6000mAH 3.2V 19.2WH weighs 141g
Let's say you want to build a small 36V pack.
You can do 10S1P with 10 x Li-ion 21700 cells, 680g.
You'll need 11S1P with x LFP 32700...