Maybe a controversial opinion, but i disagree with this
The donator status is almost exclusively used for the purpose of shiny hunting, even when you're farming xp you'd still be calling in hordes which could end up having a shiny in them, a 5% bonus for cash is absolutely not worth the 1m you'd pay for a 7 day ticket, and still not worth it anyways if you were to buy it with real money since you'd get very little profit off of it. You mentioned gym running, the average amount you'd get on a gym would be like 13500 with an amulet coin, and 5% of that is 675. If you were to defeat all gyms in a run (which takes about 2 to 3 hours) you'd get like a 20-22k bonus at best
Still, you could argue that there's no downsides to adding a new feature, even if said feature is useless, right?
wild guess here, but wouldn't "buffing" this item make RP vouchers more expensive in return?
You're just better off buying a donator status for when you're gonna either shiny hunt or level up a lot of mons, not wasting any of your time doing gym runs.