I don't think they taste indistinguishable. MO has a biscuity character that is more pronounced than what I get in Belgian pale malts. I wouldn't use Belgian pale malt if I was trying to make a really traditional British style beer although I suppose you could supplement with a little biscuit malt. I would be ok using MO for Belgian trappist/abbey styles but I don't want that biscuit character in Belgian farmhouse ales. I wouldn't use either in American or German beers, not that a lot of German styles employ pale malt.