Like other currency symbols ($, €, ¥, £, ₹, ₩, ៛, $Đ) Ȿ sticks out more than Ꞩ. Ꞩ can easily be mistaken for S, S with a strikethrough. And, if one did want to strike through it, the resultant is hard to see: Ꞩ. The descender on Ȿ draws the eye to the whole symbol.