Price stability is an issue for almost all cryptos. However, I would assume if the market reaches a more mature level with much higher market caps (maybe several billion USD) volatility will further decrease. It is quite normal that a low market cap leads to high volatility which you can observe at penny stocks for example. A low vola - not zero - would be acceptable. If you have a look at the USD/EUR conversion rate which ranged from 1.18 to 1.25 during the last weeks, several percentage points of movements seem okay.
Transaction times will decrease due to the structure of the so called tangle. This is (should be) an non-issue.
They already work on the wallet so this issue will vanish within the next weeks/months.
Good summary of the pro's.
Energy efficiency is a huge point as well. Other cryptos with POW will run into seriuos problems if they do not switch to POS. Not sure if it will be possible for all crypto projects.
I agree with you the volatility will decrease as the market grows. but I also believe that a cryptocurrency needs some tools to deal with deflation and inflation. the mechanisms holding dollar and euro constant are quit complex and I see serious issues for a cryptocurrency without such.
btw thanks for your answer! any reason you reply in English and not German?