I am not the one doing this type of direct grafting. I doubt if it would ever work. I am referring to direct grafting that @tubig did on this thread.
Top working older Sweet Cherry tree.
I thought @DennisD may did something similar but looked like he used Adara but had difficulty getting takes.
Some people do it out of not knowing. Others like to experiment. I did the apples to pears by mistake because I thought I grafted pears on pears. The result was interesting. Sometimes, accidental mistakes lead to something new.