My theory is because the pins on the socketed one are gold plated...Should make a great electrical contact. And with the ceramic package, even the chip inside might be of better quality, Cost saving is always an after thought, Ok we did it! Now how do we make it cheaper

I could be wrong but that is my guess.

My guess is the socketed one will perform higher..even if at a slight margin.

Edit: Ps:

kinda like what they did with the Classic II after the SE/30