Just did another booking using tirpla and this time it gives the option to book in USD pre-paid or pay in yen at the hotel. $385 USD vs 53,900 JPY (which today is worth $365 USD). So $20 extra -- 5% (!). I am booking way in advance (months) so I guess using it could protect me from a further decline in the dollar (which seems likely to me given current economic policies), but jeez...