When you are
traveling in Myanmar, just avoid to show big currency (100$ note US dollars) in front of the people. Using money Myanmar note is not a problem in public. Prepare small dollars note before you go to Myanmar as you need to pay for zone fee and pagoda entrance fee. To get the small note outside the city like Yangon and Mandalay is hard, so better prepare to have small note while you are traveling.
You will need small Myanmar money note for tips at hotels, guesthouse and restaurant in Myanmar as tipping is not the Myanmar traditions they will be happy for tips. Keep enough Myanmar money while you are traveling away from city like Mandalay and Yangon. Don't let's people see your big hard currency (US$ or Euro) as they all think you are rich in common.