So I'm making money every days with arbitrary things which means nothing :p
Support lines and resistance lines are simple but mostly used as indicator by so many traders... so nope they are not arbitrary at all. Don't judge technics if you don't use them or don't know how to use them. I prefer you say TA is arbitrary in that case but all the bots which are trading are using TA as this is the only way to program them, so again in that case, for me it is not arbitrary technic at all.