Spare sockets may be impossible to find, or only available as part of the complete engine wiring harness.
If it's only one of the low voltage wires that power the coil, it certainy is safe.
It's more a factor of how well the soldering job was done, and how the elements are kept out of the area that could cause corrosion.
Heat shrink tubing to seal and insulate (from electrically shorting out) the repair will last longer than wrap around tape. Electrical tape will eventually come undone and unravel because of the heat.