Well, for Bangladeshis, it is not valid an option anymore. The SGVO strongly recommends to use VFS. If in person, it might take more than 2 weeks and in that case (if you dont have strong logic and reasons documented) you are to stay back Singapore for those days. If you dont have relatives its expensive there. If they are not convinced enough, they will not accept the passports over the counter and will suggest to go back n use VFS. You can not be assured that they will return you in 2 weeks. Again they might decline accepting the emergency. So things are bit tricky here. According my understanding:
01. If anyone is visiting Singapore for any other issues, can take a chance requesting them to process it, backed with ur reasons, emergency etc.
02. If only for Canada visa purpose, it's better to use VFS as they might decline to accept the application.