I'm curious, how important is a keyboard with weighted keys for someone who is older and on her 3rd instrument? (of course this might complicate the decision making process).
I will give you an answer from my perspective - which is - a lifetime guitar player (mainly acoustic, but some electric these days) - and a piano/keyboard "dabbler" off and on for a lot of those years, as well... I have hopes of one day dedicating more time to playing piano...
I have a synth from (about) 1990 (I bought it to use with BIAB when I first purchased it). It has the standard, non-weighted keys that synth come with (A Yamaha SY-55).
I did spend about 6 month (circa 2008?) REALLY practicing piano (learning Billy Joel, Elton, John, Carole King, Randy Newman stuff). It was difficult really "getting the feel" for playing that stuff using the synth - because of the lack of resistance from "real keys". I understood that when I sat down to an actual piano. A real AHA moment. That "weight" - and the feeling of "throwing" the hammer at the strings of the piano (that is how i think of it) was INCREDIBLY important (for me, at least).
I went out and bought a Yamaha P-85. A digital piano with weighted keys. Not EXACTLY like the feel of a REAL piano, but close enough to TRULY make a difference in "how it feels to play".
I think it matters. A lot.