Is there anything wrong with fat blobby frame welds? Are fat blobby welds inferior, other than aesthetically?

Here's three examples, one's a BSO, one's a decent/good Trek and one's an expensive Felt downhill full-suspension bike.
Assuming good penetration, a “thick” weld also functions as a fillet reinforcing the joinder.  The “swirly” look is OK as long as the welding puddle is continuous.  In many instances a “stitch weld” is more fatigue resistant than a continuous bead by limiting stress risers in the weld.