Accounting costs are not an issue for me, I do the bookkeeping myself, which is not that hard if you have the right software and read up a bit on it. Double taxation is offset by the lower AHV contributions, the privileged taxation of the dividends, and the greater flexibility (spreading out payments, optimizing by combining dividends with second pillar buybacks or renovations of your apartment, etc…). Calculating that in practice is quite hard. I wrote a detailed monte carlo simulation in the past that takes into account everything and also considers stochastic variables (like stock market return, second pillar rate, etc…) and came to the conclusion that it’s better in every scenario for me (by a pretty large margin). The numbers may vary a bit for you because I live in a low tax canton and optimize taxes heavily wherever I can (calculating the ideal splits, dividing my portfolio between my LLC and my private accounts, etc…), but I did a very rough calculation here: Why do AHV / AVS / OASI contributions not have an upper limit? - #17 by 0xLambda
When you plug your numbers in there, you should get an idea of the differences (and that the fear of double taxation is probably overstated).
It depends a bit. While you pay for ALV, you do not get access to insurance money until you have completely given up your business (either voluntarily or because of solvency issues). This is usually a quite lengthy process (needs to be done by a notary and announced in the commercial register), so it will take quite some time until you get money by the insurance.
The reasoning is that ALV could be abused otherwise (when you do not have any work for a few months, you could simply declare yourself unemployed). However, changes to this law are discussed in the parliament (because COVID showed that many business owners do not have any reserves), so this may change in the future.