In reply to PTatts:
Did pretty much exactly the same as you a few years back, climbed it while doing the classic Silvretta traverse in March.
As always it depends on snow conditions. If it's icy then I would want one. If not you could get away without. It's not massively committing and the upper slopes are low angled.
If you're going from Silvretta hut to Saarbrucker in the morning the next day you might appreciate an axe for a steep icy slope just before the frontier.