Can we use copies of our certified marriage certificate for a spouse visa application instead of the original?

When we went to the local Amphur (staying in CM) to register as a 'resident' in the district.. they indicated that they would need to retain the original translated and stamped marriage certificate that we presented.. having used an agent and incurred significant expense to obtain this document i was not happy of course.. and offered them a copy i had prepared in advance for their purposes.. they initially refused this and insisted upon keeping the original.. stating i could 'borrow' back my document if the need should arise to file it elsewhere.. ludicrous imo.. so i asked them to indemnify me for the cost of engaging an agent to provide me with a duplicate in the event that they mislay (aka lose) my document and cannot return it upon making such a request.. in short i kicked up a huge fuss surrounding the cost and the fact that i needed it to apply for my Non-Immigrant O-Visa.. as well as to open a bank account.. and also to get my wife a visa to visit my home country.. the latter was poetic license of course.. and they finally caved in and accepted a colour photocopy attested with our signatures.. i was not going to leave there without it.. or a financial guarantee to replace it.. and i think they understood that in the end!