So I'm learning AutoDesk Fusion 360's Tool Library and wanted to know if anyone bothers defining their collet tool holder and locknut. Is the purpose of defining tool holders for those ones that extrude further out of the spindle than a collet?

Here are the steps I'm following:

Fusion 360 >CAM >Manage >Tool Library >

I choose my Local Library > New Library (or cloud if you've turned it on in preferences).

I then select + New Holder and then enter the following 3 entries for Height, Upper Diameter and Lower Diameter:
1 - 5mm, 21mm, 26mm
2 - 4mm, 22mm, 22mm
3 - 26mm, 25.5mm, 19.09mm

The visual then looks like a ER 25 Collet.

CAM Tool Library.jpg