Well, such things are in the Lazarus LCL code, but not in ANY FPC code...(compiler and RTL)
Never eat exceptions. You just THINK you may know which one it is, but you don't..
1. EOutOfMemory
2. EInOutError
3. EConvertError
Now.... which one do you THINK it is? All three can happen (more that just those 3).... Never eat exceptions, it is bad programmng. Always. Period.
Note StrToFloatDef is also mostly an Ostrich Approach that hides a mistake or unwanted result.
Better to use TryStrToFloat because the Boolean at least gives you a simple indication that the operation failed so you can debug it.
And it does not use exceptions. (Someone tried, got shot)