Any increase to interest will mostly go to exchanges unless there is a massive movement off exchanges, which seems unlikely. Upbit and Bittrex together hold 4,554,613 HBD. That is 44% of the total before hive.fund is removed, and 73% if hive.fund is excluded from supply. They are not giving the interest to traders, and I don't think that will change. Only 16% of HBD is held in accounts other than those 3.
IMO the increases should wait until after the hard fork.
Edit: I suppose it could be worth having the increased yield as a marketing talking point alongside the hard fork. It's just that most of the interest generated before that fork date will end up as a freebie gift to exchanges.
HF25 solves this with interest getting paid only on savings. The exchanges can put the assets in savings, but by doing so they need to wait 3.5 days to withdraw it and so most shouldn't. Exchanges could offer staking incentives to users and stake it themselves, and send users a % of what they get.
The fork honestly shouldn't be too far off. Raising it now might mean they get a month or two of payouts before the switch occurs, and from what I see, some witnesses want to go even higher, but only after the fork for reasons like this.
Why would people hold their HBD in an exchange when they can put it in an HBD savings account and get interest on it? Would they not care to get the interest themselves?
I expect this shift to happen over time, but not immediately, so @demotruk is likely correct that exchanges will get a windfall at first.
You could also view it as an incentive for exchanges to support HIVE/HBD.
Because the vast majority of crypto speculators generally don't know what they are buying, and passively hold on exchanges in ignorance.
Higher interest is likely to result in a large amount of HBD moving off exchanges, at least unless exchanges pay interest to customers, which they probably won't for HBD (due to it being too small to justify the effort on their part).
Right now there is no meaningful incentive to move your HBD off the exchange. But compare with HIVE where there is a lot on exchanges, but nowhere near 70%. That's because there actually is a reason to take your HIVE off the exchange and stake it.
True, any movement won't happen immediately so the first effect is a windfall to exchanges, but you have to start somewhere, in a chicken-and-egg fashion. You can't wait for people to move their HBD off exchanges to start paying interest, because they won't.
My point being that the gift doesn't happen if we wait for the hard fork. Assuming the hard fork goes ahead at the end of June, the exchanges will get about $25,000 in interest this month with this increase.
I do see a benefit in getting ahead of the hard fork for the sake of marketing - it would be better to generate some attention towards Hive Dollars alongside the upcoming hard fork so that the point of the savings interest is not lost (if 3% interest is mentioned in articles about the hard fork crypto speculators will see it as a joke).