A local copy is inherently fragile. It's easily destroyed by accident, flood, fire etc. This is especially true when using a single storage device like an SD Card, vs the way that these storage services operate, leveraging things like erasure encoding.

Local backups are important, they're cheap, and often fast. They just shouldn't be the only kind of backup you do for data that is important to you.

Make two local backups and store the other one at work or a friends house.