At the supply houses, we get the foam insulation with self stick.
The foam is split, you slide it over the pipe, and pull out the clear plastic strips covering the adhesive.
Then you can push it together.
If you don't have that, then the ties may be a good idea.
The home center insulation doesn't have those features.
Their customers only worry about cost.
Plumbers worry about time, and not having to go back.