In "Bits Acceptable Use Policy / Now the Don’ts that constitute violations of this policy:" we can see that it is included in don*ts "graphic design services". I think this is totally wrong. Why I am thinking that? 1st you (Twitch) loosing a large amount of money because of that and there is nothing wrong with offering designer services in exchange for bits. You like it or not, bits are some kind of currency and streamers using it for all kind of things on their live streams. If you really want to push this "Now the Don’ts that constitute violations of this policy:" policy in a wide meaning you will have to ban half of a twitch streamers. In a nut shell bits only can be used to be gifted to streamer without asking anything in return from streamer and I agree with that because that mean "no return back when u make a gift in bits" ,,, but, someone gifted me some amount of bits and because I want to thank him on some way I would make some graphic design for his twitch,,, is that against Bits ToS? You see, there is nothing wrong with that. There is no exchange, there is only good will between us. Of course you can turn that around and say that this was some kind of payment. Well, maybe you dont know but everything is some kind of payment.
2nd. If you remove "graphic design services" you will get a lot of designers from other platforms which are made for that kind of services. What I am offering on my Twitch channel? Someone who need some graphic design can watch me working on that what he/she need (graphic design). This is excellent! Because he/she can make corrections till I working and whole job will take less time than if I doing it on some other site dedicated to graphic designers and selling their services. You see where I am going and why twitch is way better place to sell graphic designs than other sites on web?
In short ...
By removing "graphic design services" you will get a lot more transfers/use of bits, which is probably what you want from users to do. Designers and people who use designers services will not be scared of ban on twitch. You will get a ton of designers from other web pages who will like to offer their services on twitch because on twitch is way way easier to do graphic design stuff for wide variety of customers just because customers can interact with designer in a process of design which is base of good, quick and satisfied customer in a graphic designers world.
OK, I hope you got it on a right way.