• Small amount of material needed (it's very cheap)
• Therefore fast printing time (you can make a lot of them)
• 2 parts to be combined with dovetail (for perfect alignment)
• Optimized capsule movement through elevated sliding rail (bulge on the flat side does not lead to stuck capsules)
• Ability to take out capsules at the bottom
• Space for 10 capsules
• Printing footprint: about 18x10cm

Remark: This is my design which has originally been released on thingiverse about 10 years ago. Various remixes are available there as well.

https://www.thingiverse.com/thing:205728