Depends on the toaster oven. There are some really good ones out these days that are very accurateGrandpa had a huge industrial workshop with like 20' high ceilings as I recall. He did decarb his rosin in a toaster oven though. For flower you would need to work in pretty small quantities to get it done in a toaster oven I would think.
Also, temp control would probably be more accurate in a regular oven?