Currency of other countries fluctuate as well with value over USD but rent does not change every month does it?

You have a point but that still heavily depends on the length of the contract ^{[both parties should respect it]}...

e.g.

Imagine renting a place for "a month" in a country with high inflation rates ^[regularly]; I think it's safe to say that you're not going to get the exact same rates for the renewal of that contract ^{[it'll be a revised version with updated rates]}.

and you can convert your bitcoin in their local currency.

Any type of conversion prior to "directly" paying a bill or purchasing a service with BTCitcoin, defeats the purpose of using it as a currency.