Map updates?

Do it over night if you're concerned about time.  With maps, I find the times to be on them to be very high side for updates (it will likely take far less time), and it's really not a "extra" 10gb", just a replacement to one that's already on the watch.

I'd do it.

you don't need to update the map unless you wish for your map to be updated. Is this really a sensible question to ask? :D

Also, take into consideration that 2019.10 update will leave you with almost 3GB less free space (for EU maps, less than that for US maps) because it adds additional gmaprda.img Road Drawing Accelerator file.