Yes, Backups!
But another "additional" trick is download empty.html to a scratch folder, drop the files on that, once finished drag export/import the tiddlers to the destination. I use an implementation of JSON mangler in a wiki on Bob.exe for all this conversion work, unless I need to do reoccurring imports in the primary wiki. TWaaS
JSON mangler can import and convert csv, JSON and more and can generate a plugin containing the tiddlers, potentially saving space, especially by not including unneeded data.
Regards
Tones