Getting variable type in Autohotkey - autohotkey

Question

Why does this work to determine the type
if delay is integer
{
MsgBox You set delay = %delay% seconds
return
}
else
{
MsgBox "%delay%" is not a valid number.
goSub, input
}
But not this - this also allowes non integer values, as long as it's greater than 0
if (delay is integer and delay > 0)
{
MsgBox You set delay = %delay% seconds
return
}
else
{
MsgBox "%delay%" is not a valid number.
goSub, input
}
Both snippets are for checking the result of an input box. The script is meant to help extracting a movie or sth. while u still download and already watching it after having finished the first part or so..
Here's the full script in case someones interested.
delay := 120
help = Help - Unzip Auto Extractor`nF1: Help`nF2: Get Unzip Window`n(must be in foreground)`nF3: Set unpack delay (seconds, default 120)`nF4: Start or stop unpacking`nF5: Exit
MsgBox %help%
F1::
MsgBox %help%
return
F2::
WinGetTitle, title, A
MsgBox Selected window "%title%"
return
F3::
input:
InputBox, delay, Set extraction timeout in seconds..,Use numbers only,,,,,,,,%delay%
;InputBox, OutputVar [, Title, Prompt, HIDE, Width, Height, X, Y, Font, Timeout, Default]
if delay is integer
{
MsgBox You set delay = %delay% seconds
return
}
else
{
MsgBox "%delay%" is not a valid number.
goSub, input
}
#MaxThreadsPerHotkey 3
F4::
#MaxThreadsPerHotkey 1
if KeepWinZRunning
{
KeepWinZRunning := 0
return
}
else
{
KeepWinZRunning := 1
}
Loop
{
Loop %delay%
{
sleep 1000
if not KeepWinZRunning
{
break
}
}
if not KeepWinZRunning
{
break
}
ControlSend,,{Enter},%title%
}
KeepWinZRunning := 0
return
F5::
ExitApp
return

Answer 1

I think this quote from autohotkey If var is [not] type documentation will answer your question:
Note: The operators "between", "is", "in", and "contains" are not supported in expressions.
Note the second example work fine for me regardless of this rule.