Intermittent welding is a joint welding technique where the fillet weld is done non-continuously.
Apart from the fact that it’s more economical (since less energy and materials are used), it is also easier to repair.
Since the welding is not continuous, in a case of failure, only a small part of the welding is broken before the strain is released, thus making it easier to repair. Had the welding been continuous, the entire joint would have been torn apart, requiring the re-welding of the entire joint.
Naturally, for the very same reasons, intermittent welding is not as strong as full welding.