I got reply by Expedia support. Theyre apparently use Coinbase but only for US users. So you might have to calculate extra fees (minor).
I tried to book Brussels on chepair http://www.cheapair.com/hotels/search-results.aspx#!Dst=Brussels,+Belgium&arrivalDate=2015-05-16&departDate=2015-05-18&LocID=10000690&KT=M&Rms=2&af=&pf=&sf=&pn=&aaa=0&pp=0&hss=H&pg=1 with 18 hotels available under $81. The low offer on bitcoin sites is what is most annoying. Expedia's Hotel site shows 147 http://www.venere.com/belgium/brussels/#p|1;f:o|venere_ranking-t|all-z|all_areas-r|r2-c|all_rate.
Expedia confirmed plans to extend Coinbase services to other Expedia owned platforms, but only US Expedia.com users can enjoy this at the moment.
It was also said that all is calculated in USD (refunds ...). This indicates, that even when hotel.com allows bitcoins only US (or proxy) users .. So we better book all in advance when before travel