convenient? The quickest with the least amount of programming knowledge.... and given the appearance of your data ... would be to 'int' it so that you get a table. If this yields too many classes for a table to be generated, then a reclass to an integer scale would be the 2nd quickest since this would be guaranteed to produce an integer raster, a table, a cell count... which multiplied by cell area (cell size squared) will give you the area of each class.
