My mum has an iMac with a 3TB fusion drive in it and she's running out of space. She loves photo and video editing. She's good with final cut but not with managing separate storage. SSD's do not go up to that size and if they did, they'd be massively expensive. The fusion drive still uses regular storage under the hood for the majority of it as far as I can tell.
Would it be a good idea to move her home directory to a fast external hard drive? Say I get her a thunderbolt 3 capable hard drive with 8TB or 12TB, like the LaCie's. She doesn't have to try and manage several drives for her work, but she does have a ton of space afterwards. Are there any performance concerns or upgrade issues I should be aware of?