present my opinion at first:
1. the fee should be high enough to protect users from spamming blockchain.
2. the fee should be low enough to encourage users to transfer/trade without too much worry.
3. the referral program is ok, however the fee rate should be determined based on more research and consideration.
4. $0.005~$0.04 for each transfer should fit.
the referral program is built to balance CAC and LTV for a well formed business model, this is really interesting idea however more details need to be checked exactly while implementing it.
the LTV comes from the fees the new users pay, it depend on the transactions the users complete and the fee for each transaction. below diagram shows clearly that not high fee rate, but medium fee rate bring the highest LTV.
so is $0.2 for each transfer high or low? to get a conclusion need some research, however now what we can see is the very low transaction volume, users are discouraged to transfer,clearly.
we need to let the users enjoy to transfer/trade, if users hate to transfer/trade there's no way to build a well formed ecosystem, and nowhere to generate profit.
I found below sentences in Bitshares blog, seems it explains the logic behind the high fee policy:
"While low fees are important, undervaluing the service provided is counter productive. For this reason, BitShares charges a price that is much higher than competing cryptocurrencies but much lower than traditional exchanges and payment networks like Dwolla or PayPal."
if low fee means undervaluing the service provided, then I do not agree the logic presented above, apparently BTS is awesome and referral program is ok, but as shown above, high fee not necessarily bring high revenues, PayPal charge high however Alipay are free but they both provide high value service, users from China, North America hate high fee and I think US users do not hate low fee,in Internet service area it's trend to charge low in fundamental service but charge high in advanced service, and create new ways convert traffic to revenue.
recently, many show their happiness for the reduction in BTS supply, however I fall in different feelings, these days in BTS relevant QQ groups the most frequently sent expression is "hug together and cry", many users show their disappointment and confusion, very rare transfer occured after the launch of 2.0, I think not only users in China, but also users around the world, including US users feel alike, otherwise the very low transaction volume can not be explained.
all these factors should be considered, and research need to be done to find the right fee rate to make a balance. in my opinion $0.2 is too high, $0.005~$0.03 is more reasonable, medium and acceptable, and seems to generate the highest revenues, hope more data can be collected to suggest.