ConTeXt: Define command for table

Why is it not possible to define a command to create a table like this? I had no problem doing the same with a list

List Command:

\define[1]\docListBulleted
{\startitemize[before={\blank[small]},after={\blank[big]},inbetween={\blank[small]}] #1 \stopitemize}


MWE:

\define[1]\tabd
{\startxtable
[option={stretch},split=yes]
#1
\stopxtable}
\starttext
\tabd{\NC  Elements \NC Amount  \NR}
\stoptext


The same (or similar) error occurs when I try to define the table with /definestartstop

MWE:

\definestartstop
[Asdf]
[before={\startxtable},
after={\stopxtable}]

\starttext

\startAsdf
\startxrow
\startxcell
dddd
\stopxcell
\stopxrow
\stopAsdf

\stoptext


Extreme tables (aka xtables) are implemented using Lua buffers. These do not play well with macro definitions because the starting command has to “see“ the stopping command. From the manual:

Also apart from it not working, you should not use \definestartstop to wrap an xtable. Just use \definextable instead.

\define[1]\tabd{%
\startembeddedxtable
[option={stretch},split=yes]
#1
\stopembeddedxtable
}

\definextable
[Asdf]
[option=stretch,
split=yes]

\starttext

\tabd{\NC  Elements \NC Amount  \NR}

\startxtable[Asdf]
\startxrow
\startxcell
dddd
\stopxcell
\stopxrow
\stopxtable

\stoptext