Like under 50Ohm or something?
Or would it be the same as having a cheap AMP?
Some low impedance headphones have low sensitivity, this means that they need a lot of current to sound loud. This headphones need extra amplification to sound good. Some examples are AKG K701 or Hifiman He500.
If you talk about low impedance headphones with high sensitivity (those that sound loud plugged into any portable device) then the answer is yes for some headphones, and no for other headphones.
"A chain is no stronger than its weakest link"
If you are using low quality headphones, probably you headphones are the weakest link. Then upgrading other link (the amp) is not really useful.
On the other hand if you are using high quality headphones, probably the weakest link is you Amp. In this case, upgrading the Amp can make a big improvement in terms of sound quality as long as your DAC and recordings are also high quality.
Hope that helps!