Elastic-only waistbands are the simplest option found on most waist-style cycling shorts, especially in budget to mid-range models. They can be perfectly comfortable and secure—if you get the right size. The lack of any adjustment mechanism means you're relying entirely on the fabric's stretch and your sizing choice to keep the shorts in place.
The upside is a clean, lightweight design with no bulk or pressure points from drawstrings or hardware. The downside is that there's no way to fine-tune the fit mid-ride. If the shorts are even slightly too loose, they can slip or roll down; if too tight, the elastic can dig into your waist and restrict breathing during harder efforts.
Elastic-only waistbands work best if you're confident in your sizing and prefer a minimalist feel. If you're between sizes or have trouble finding shorts that stay put, consider a drawstring or wide comfort waistband instead—or skip waist shorts altogether and try bib shorts for the most secure, comfortable option.