What does the `-context` parameter mean when using FFV1 in ffmpeg
The coder here refers to the process used for entropy coding the error residuals. The context size sets how many neighbouring residuals are considered in this process.

As to the relative benefits, have no particular experience here, but since this is a lossless process, the tradeoff will be between time, size and resource use. This latter question is better suited for https://dsp.stackexchange.com/