call vs newobj in struct initialization

Program.cs

using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace Test
{
    public class Program
    {
        public static void Main(string[] args)
        {
            var dangerousStruct = new TestStruct(0);
            dangerousStruct.X = 5;
            dangerousStruct = new TestStruct(0);
            
            /*
            Release mode:
            
            IL_0000: ldc.r8 0.0
    	    IL_0009: newobj instance void [StructInitTest]TestStruct::.ctor(float64)
    	    IL_000e: pop
    	    IL_000f: ldc.r8 0.0
    	    IL_0018: newobj instance void [StructInitTest]TestStruct::.ctor(float64)
    	    IL_001d: pop
    		
    	    Release output:
    		
    	    0
    	    0
    		
    	    */
    		
    	    /*
    	    Debug mode:
    		
    	    IL_0001: ldloca.s dangerousStruct
    	    IL_0003: ldc.r8 0.0
    	    IL_000c: call instance void [StructInitTest]TestStruct::.ctor(float64)
    	    IL_0011: nop
    	    IL_0012: ldloca.s dangerousStruct
    	    IL_0014: ldc.r8 5
    	    IL_001d: stfld float64 [StructInitTest]TestStruct::X
    	    IL_0022: ldloca.s dangerousStruct
    	    IL_0024: ldc.r8 0.0
    	    IL_002d: call instance void [StructInitTest]TestStruct::.ctor(float64)
        	
    	    Debug output:
        	
    	    0
    	    5
    		
    	    */
        }
    }
}

StructInitTest.il

// Metadata version: v4.0.30319
.assembly extern mscorlib
{
  .publickeytoken = (B7 7A 5C 56 19 34 E0 89 )                         // .z\V.4..
  .ver 4:0:0:0
}
.assembly StructInitTest
{
  .ver 0:0:65535:65535
}
.module StructInitTest
// MVID: {87E574D7-FDDD-4E55-9A84-09B93E156F07}
.imagebase 0x00400000
.file alignment 0x00000200
.stackreserve 0x00100000
.subsystem 0x0003       // WINDOWS_CUI
.corflags 0x00000001    //  ILONLY
// Image base: 0x0000001C4C130000


// =============== CLASS MEMBERS DECLARATION ===================

.class public auto ansi sealed beforefieldinit TestStruct
       extends [mscorlib]System.ValueType
{
  .field public float64 X
  .method public hidebysig specialname rtspecialname
          instance void  .ctor(float64 y) cil managed
  {
    .maxstack  8
    
    // This value type is purposefully left uninitialized.
    
    ldarg.0
    ldfld float64 TestStruct::X
    call void [mscorlib]System.Console::WriteLine(float64)
    ret
  } // end of method TestStruct::.ctor

} // end of class TestStruct