Basically, I have nothing against the Velcro strap instead of the normal plastic part.
But the Forerunner is now to be clipped to the thin support pins back and forth seems to me relatively fragile.
Since there are far better solutions.
I'll make me a thick Universal rubber part on the handlebar and attach the Forerunner with the long strap to it.
The departure risk is me on a mountain bike in the Garmin system then too high.