Hey @mathiasb,
thanks for sharing this. I was wondering in general about the ledger fee when I digged a little bit deeper into ICRC-1.
Personally I would like to know the reason for having a fee at all in case of token transactions. Is the main reason for that to prevent cycle drain attacks by spamming the network with low-value token transfers?
Is it possible in the reference implementation to remove the fee? According to the following posts it is not:
It was also not 100% clear to me where the fee is going and what it is used for. According to the standard, there is a Minting Account that can create new tokens and also receives the fees of tx’s which are then considered as burned. Also, transfers of tokens to the minting account seem to be considered as burned and not included in the icrc1_total_supply.
What’s interesting and a little bit confusing here, is that the ckBTC (also an ICRC-1 token) documentation mentiones that the 0xfee subaccount of the ckBTCminter collects the fees which will then eventually be used to cover cycles costs in the future. While that makes sense, those tokens are not really burned then, are they?! 
This subaccount has already collected roughly 0.19 ckBTC and I assume that those 0.19 ckBTC are not included in the response of icrc1_total_supply on the ckBTC ledger canister. So are they burned or not? According to the docs of ckBTC they are not and can/will be used in the future, e.g. to cover cycles costs.
Do we generally have an overview on how ICRC-1 tokens can be configured using the reference implementation? I assume it is also possible to deactivate minting which would lead to a deflationary supply in case the fees can really be considered “burned” 
IMO it would be awesome if we could remove the ledger fee completely if desired. E.g. for each transfer of ckUSDC, the user currently “loses” 0.01 ckUSDC because of the fee. While this isn’t much, it is still less than before. For a stablecoin this might be ok, but for tokens which have huge price fluctuations, these fees might need to be updated on a regular basis.
Also, for ckBTC we currently have a fee of 0.0000001 ckBTC per transfer. It would be great in terms of marketing being able to promote that BTC could be transferred with zero fees on ICP.
Happy to get some feedback on that topic 