UPDATE JUNE 2021
After 18 months of working fine, the keyboard suddenly stopped functioning. It just won't switch on. From what I read across other reviews, this is not an exception.
Sending it back to Thomann for repair (thank God for the warranty), but really disappointed in Yamaha's quality standards...
You will read it in a lot of reviews: the PSS-A50 is trying so hard to punch above its weight it ends up disappointing.
Granted: Yamaha was full of good intentions with this keyboard but did have to make a few compromises.
Now look at it from the other angle: this is a below 100€ keyboard. For a fraction of the price of a Reface, you notably get:
the same keys than the Reface series with velocity sensors,
a compact but playable format,
tons of voices + some effects (pitch, modulation, etc.),
100+ 'arpeggios' (loops you can play over)
a basic but fun one track recorder
a MIDI connection to use it as a master keyboard,
and a lot more...
So yes, the only speaker doesn't sound great,
yes, the usability of some functions is questionable,
and yes, "overall it could have been better".
However at that level of price, I challenge you to find any competitive keyboard that does better.
Just take the time to learn how to make the most out of it.
Definitely having a ton of fun with mine x Garageband.
Highly recommended as a travelmate or family mini-synth.