I put my 1st straight into a cot when he was born and then used a woven cane bassinette for my 2nd baby and will use it again this time. We were in Darwin when I had my dd and her bassinette kept her safe and cool it was great. Have you asked your mum why she's so against bassinettes? maybe there's more too it than she's saying.
I think it's just a personal preference, some people really like them others don't, for me I like having baby next to my bed for the first few months and the bassinette seems to work well for us.