I really wish (this is a wish, feel free to keep going if this “debate” is very important to you) we could avoid the “toys instruments versus not toys instruments”. It’s probably the debate I dislike the most even worse than digital vs analogue (and I really dislike digital vs analogue).
They’re all toys, you’re never gonna cook food, build a house make an organ transplant with a synth, wether it’s a Moog One or a Monotron. Similarly, you’ll be able to reach great creative depth, subtelty, emotions, using either a Moog One or a Monotron, so maybe both of them aren’t toys in the end? Whatever.
The Volcas are cheap, some synths are less cheap, cheap gets you limitations, volcas are well concieved within those limitations so that if you came for what they offer, they can be of great use for as long as you need what they offer.
Some other synths have less limitations or more sturdy components and so they’re more expensive.
Toys are things we play with to enjoy our time and have fun. They’re by definition either all synths, and to some extent all instruments, or no instruments at all, depending on how you consider music.
The Volca Modular is wonderful. Extremely characteristic in the way it sounds, but there’s a lot you can achieve with the way it sounds too that it’s not easy to achieve even on much more expensive offerings.