It's a bandaid and not a particularly good one. Spotify reserving a ticket allotment is really no different to American Express doing the exact same thing. Amex uses their allotment to attract premium members through concierge services. Spotify doesn't quite have this same upsell potential (yet?) but they're doing it to make money. We just don't know how that'll happen yet.
Defeating bot buyers, scalpers and resellers would actually be a noble goal but its' really the tip of the iceberg. If anyone was actually interested in tackling this (hint: they aren't) then you need to tackle a much bigger problem: the venue monopoly with Ticketmaster and Live Nation.
Many venus, particularly larger venues, have exclusive contracts with Ticketmaster. Ticketmaster also has an official platform for reselling tickets, of which they get a cut. In a more equitable world, you would only be able to resell tickets for their face value. It's alleged (and I believe this) that Ticketmaster only releases a tiny portion of tickets to the general public. The rest they have arrangements to sell through scalpers and resellers and their own platform because, hey, they make more profit that way.
There was a time when businesses were a tool to generate income. Small businesses still work this way. But any sufficiently sized company now is just a tool to speculate on and make a capital gain on. Ticketmaster doesn't need to grow into a trillion dollar company but they want to and, at a cewrtain point, the only way companies can continue to grow is by cutting costs and raising prices.
Back in the nascent days of Internet music piracy it was pointed out that almost no bands make enough money from selling music to live on. It's why the biggest anti-piracy advocates were huge bands like Metallica. Most bands make their living for performance fees ie playing concerts. And even then they might make barely enough to cover gas. What really gets them over the line is selling merch at the venues.
I'd say that music would be in a better state if bands could see more of the value of their labor from playing concerts. But even concerts aren't about bands or their fans anymore. They're about upselling premium services to high-net-worth clients. You ever notice that at sports venue, for example, general seating always gets mysteriously ripped out and replaced by suites? Same principle: venues make more per square foot from a corporate suite than they do from sports fans. There was a time when ordinary people would be fans of their home teams and just go to every home game. That's increasingly out of reach.
In short, the entire system is broken. Spotify participating in it won't change anything.