Both classic tar soap and this shower gel are based on the idea of tar-containing cleansing, but this product is specifically a liquid body wash with birch tar extract. That matters if you prefer a product you can spread quickly over larger areas, especially the back, shoulders or chest, rather than working up lather from a bar.
The gel also includes cleansing agents that create foam and help lift away dirt, sweat and surface oil. Glycerin is included to help reduce the tight feeling that stronger cleansers can sometimes leave after rinsing. This makes the product suitable for people who want a tar-based cleansing step in a shower gel format, especially when the skin feels oily or unclean quickly.
It is still a rinse-off cleanser, so it should not be used like an intensive leave-on product. Massage onto wet skin, rinse thoroughly and avoid the eye area. If you already use targeted products on certain body areas, this gel can fit as the washing step before the rest of your routine, provided your skin remains comfortable.