Index fund managers use it to build a portfolio that will track the overall index. For a tiny component like AMBT this may not have any significant impact since the investments are weighted based on their proportion of the actual index. This allows fundies to replicate the performance of the index. It is possible that it will increase institutional (and retail) investors who consider the index a qualification for investment...and we qualified! Having seen this stock in thinner times, it is amazing to me we are exchange listed and index listed. Like you said, it just gives us a little more visibility. It probably boosts the volatility, as well.
imo
gl
Always do your own due diligence. Never trade securities based on non-professional advice from the polka community.