Not in cases like Kiss, Bon Jovi or Def Leppard, where the sole reason seems to be record sales.
"that boxset isn't on Spotify, but Begin Here is"
That's too bad. Lotsa key early gems missing from that album. Also, the s/t US version is arguably stronger (includes "Tell Her No", "Sometimes" and "It's Alright With Me" and has a better track sequencing in general). But "The Original Studio Recordings" might be the best option despite the bizarre format.
"I do like the Blunstone solo album One Year, for what it's worth."
Same here, though it's obviously pretty different from The Zombies. But it means that you're not completely hopeless and you may also wanna check out that post-breakup "Into The Afterlife" comp