担待 has a colloquial, slightly polite-old-fashioned ring. The 'please excuse me / please bear with us' use is the more common one in everyday speech — set phrases include
多担待 ('please be patient with me/us'),
还请您担待. The 'take responsibility' sense is sturdier and shows up in serious contexts (offering to shoulder blame). Both senses share the core image of
担 'shoulder a load' +
待 'handle/treat'.
