The general deal with a softer than average sponge is if the topsheet isn't iron hard, you can get penetration into the sponge much easier, often with a weaker swing.
The advantages for this are:
1) Easy to generate some spin with a weak swing
2) Easy to generate heavier spin with a 40% swing
3) Easier to generate topspin on BH, since many players have a very weak whip on BH
4) Makes a nice loud sound on a violent impact vs incoming topspin
5) Easier to do a soft topspin loose grip shot at low power, such as a roll or light flip or light defensive topspin shot
6) Easier to do a 20-30% power loose grip counter topspin vs incoming topspin loops and land it
7) Possible to make extreme spin on serves if bat speed, grip, whip, and impact are right
8- In general, easier to make some spin and control with a weaker swing and weaker grip
The disadvantages are:
1) Smashing lacks power and ball goes everywhere
2) Driving the ball close to the table with force has less control
3) Counter-looping with violent force sounds powerful, but is seriously lacking power
4) Powerlooping an underspin ball is less powerful and harder to control
5) Pretty much anything with more than 50% power lacks power and has worse control
The PUNDIT argument is that a beginning and developing player ought to use a soft sponged rubber with controlled strokes using 20-50% power to get a feel for the ball and to generate spin (and hence control on topspin offense/defense)
The PUNDIT way works, it isn't the only way, but it works, time has proven it.
Later, after a foundation is established, a player moves on to a more offensive oriented rubber/blade suitable for the style they are trying to play.
That particular way of the PUNDIT is a pretty sound way IMO as well.
Sounds like I am a salesman for PUNDITS, but anyone following the forum over the years knows I have put myself center of mass in the cross-hairs of many a pundit. I guess at heart I am a pundit, but not the classic one way or the highway type.
OP, do what your heart, your coach, your friends, the internet trolls, and wind lead you.
Whether you go the soft way, or the middle of the road control rubber way, a version of Aurus is right in the middle of the zone of appropriateness... and in Europe, you can find it on sale often at a reasonable price, plus that rubber lasts a heck of a lot longer than average rubbers.