Well, I sometimes use the road through Lihula between Pärnu and Tallinn ;) But driving from Türi to Tallinn, this I'd definitely use this road. I haven't tried from Pärnu though ;) 
There are several examples of more intuitive marking in Estonia (for instance: in Rakvere). It would be good to at least mark the Rapla bypass (20125+20141) with the same category as the road that goes through Rapla town center ;)