My concern w/ these home-base cellulars vs a landline is talk quality.
When I use a cell ph and talk to another cell ph user, there are all sorts of interruptions when both try and talk at once. Normal conversation is hampered.
When at least one is a landline, it is not quite as bad.
Maybe MJ or similar VOIPs are clearer ?
OTOH, I also wonder if the cell reception indoors with units like the OP mentions isn’t radically superior to a regular mobile phone because of it being amplified w/ big power from elec line.