They can be used for Travelling but with limited movement and in a restricted direction. With Pas-de-basque, the movement can only be on the first beat of the bar and, if sideways or diagonally, should preferably not be to the left on the step starting with the right foot or vice versa.
The Strathspey setting step is equally unsuitable for movement toward one side using the step starting with the other foot; however, it is so similar to the Strathspey travelling step that, when used for this awkward movement, it loses the characteristic sideways style and so becomes, apart from a few centimetres difference in the Position of the closing foot on the last beat of the bar, virtually indistinguishable from the Strathspey travelling step.
Blessedly, the few old Scottish Country Dances which do require these uncomfortable movements have largely fallen into desuetude.