Two caveats for your yuh calculation:
That’s absolutely something to keep in mind. At SQ at least it’s “only” the 0.15%.
Very true. Hopefully more ETFs will be added over time.
If I had to do it with yuh, I’d go with the All-World High Dividend or the MSCI World Minimum Volatility in CHF.
Ok, so i finally opened an account to check how it’s going, and wired a few hundred CHF.
It works as intended so far. Here some observations:
The app transparently says “max 0.5% markup on FX”. my so far two data points tell me about 0.2 and 0.35% compared to rates at www.exchangerates.org.uk, however that is within a day’s volatility so to be fair I’d have to wait for several more transactions to compile an average value.
there seems to be a fraction of 2% liquidity that you cant get rid of. so de facto 98% stocks in that portfolio.
the statement comes ony as PDF, nerds like me of course prefer csv, but hey. On the other hand it’s really detailed, which I commend.
Due to findependent acting on swiss intermediary, stamp tax applies. Which is nicely presented in the report, together with very small exchange fees. Together they amount for 0.14% of my initial deposit/ investment.
If anyone would like a referral code, pm me please 
each referral is worth CHF 4.4 p.a. for life against the all-in fee of 0.44%.
All else it works identically to Viac or finpension, simply outside of 3a
Thanks for describing your experience.
Small clarification, the exchange is irrelevant. The stamp duty tax applies to all Swiss financial intermediaries (brokers, wealth managers), independent of what stock exchange is used.
Oops, here my non-experience of swiss intermediaries shines brightly 
I just corrected this above