powershell - What is the difference between [Regex]::Replace() and -replace?

Question

I understood the difference between .Replace() and -replace, but what are -replace and [Regex]::Replace()?

I tested the 2 following codes, but for me the results are the exactly the same.

I also referred to PowerShell Cookbook(O'reilly), and it says

([Regex] is) extremely advanced regular expression replacement

I want to know what [Regex] can but -replace can't.

$line = "Loosen the socket by turning it#counterclockwise."
$line = $line -Replace "([a-z])#([a-z])","`$1 `$2"
$line

# Loosen the socket by turning it counterclockwise.

$line.GetType()
# IsPublic IsSerial Name                                     BaseType
# -------- -------- ----                                     --------
# True     True     String                                   System.Object

$line2 = "Loosen the socket by turning it#counterclockwise."
$line2 = [Regex]::Replace($line3,"([a-z])#([a-z])","`$1 `$2")
$line2

# Loosen the socket by turning it counterclockwise.

$line2.GetType()
# IsPublic IsSerial Name                                     BaseType
# -------- -------- ----                                     --------
# True     True     String                                   System.Object

Answer 1

-Replace is a powershell operator that replaces X with Y and cannot be configured to do anything else.

[Regex] is a .NET class which contains a method called Replace and has many overloads that can configure and control how the string is replaced.

-replace probably uses [Regex]::Replace under the hood.

The reference to the Regex.Replace method contains all the many different ways it can be called.

The methods and properties contained in the Regex class.