Or a U3S https://qrp-labs.com/ultimate3/u3s.html which can band hop but is larger than the WSRPlite.
Am I missing any important point which could lead me into acquiring a WSPR hardware and software?
The no QSO part of WSPR can be a burden for some “strict” countries. The SW does not issue “QRL” or listen for any activity on the frequency it will just transmit the WSPR message.
I WSPR at my home QTH. For a given power level I can be spotted in VK, ZL, or W land if the propagation is good. I use 0.5 to 1W at the moment. I’ve tried RBN (honestly just once and sent the code via fldigi), no spots even with my paltry 5W max. I know there are local skimmers in JA and they didn’t even hear me.
One issue for WSPR is if you don’t follow the suggested frequencies in use you will NOT get spotted! RBN is more lenient in this regard.