Shield Swipe is an obvious DPS increase and a net gain in TP. Therefore, it will not impair the number of Halone combos used over the course of the fight. Assuming you end the fight near 0 TP, it is free damage that in the long run will establish more damage and threat than not using it. It is, of course, only viable when you have an established threat cushion. It's viability also declines in fights that do not last long enough to TP starve you. I am currently on Turn 5 and have only been TP starved in Turn 1.
It is an ability with limited uses (and one I hope gets looked at in the future to be made more interesting), but it still has a place on the action bar.