That is Excel team's choice, of course. However, I would have thought that it would be based on the usefulness of the given import type currently, not in 1988 (I trust there have been new import filters since)
How many SYLK files did you see recently, e.g. within the last 30 years? For me, the result is 0 (zero). As compared to innumerable swarms of CSVs of all flavors. Yet even MSO2013 prefers Yonder Hiftorical Curioufity; whence Excel's fondness and preference for obscure and rare formats, I have no idea.
And yes, giving user at least an intelligible error message would be nice (I hold no illusions that popping up a selection would be a complex feat: import logic is usually a gnarly place).
How many SYLK files did you see recently, e.g. within the last 30 years? For me, the result is 0 (zero). As compared to innumerable swarms of CSVs of all flavors. Yet even MSO2013 prefers Yonder Hiftorical Curioufity; whence Excel's fondness and preference for obscure and rare formats, I have no idea.
And yes, giving user at least an intelligible error message would be nice (I hold no illusions that popping up a selection would be a complex feat: import logic is usually a gnarly place).