Most cases rely on a combination of evidence yes, but circumstantial evidence features very prominently within that. My statement that most conviction rely on circumstantial evidence did not state solely and is correct! I have provided some sources below that talk about the validity, importance and use of circumstantial evidence below to evidence my claims.
We delve into two cases which show that the details matter when judges are considering whether a will should be set aside for undue influence.
www.ashfords.co.uk
You assertion that direct evidence is stronger is also not accurate, especially if that direct evidence is eye witness testimony which can be very unreliable and again have cited sources below that evidence this.
Research indicates that circumstantial evidence can result in convictions when it has a logical and compelling narrative. Though it requires inference, it is treated with equal weight as direct evidence when the evidence is strong enough to meet the burden of proof. Eye witness testimony based on one study was responsible for 75% of wrongful convictions. Again sources below.
https://repository.uclawsf.edu/cgi/viewcontent.cgi?article=1043&context=judgesbook
Psychologists are helping police and juries rethink the role of eyewitness identifications and testimony.
www.apa.org
A nonprofit news organization covering the U.S. criminal justice system.
www.themarshallproject.org
Most convictions are garnered on a combination of factors and evidence type and one is not necessarily better than the other and its accurate to say that most convictions rely (to differing extents) on circumstantial evidence but as you rightly stated combined with other evidence types also.
I am still waiting for your source of 14% because last I checked those type of statistics are not tracked and measured.