I can agree with this. This is true, on the one hand.
The fact is that the so-called "stable versions" regularly crashed for one reason or another, something didn't work, and so on, so the program is stable in only one aspect.
In this case, the user buys a product that de facto ALWAYS has problems (I don’t remember a single stable version in which there would be no problems). That is, to call a "stable" release that has problems is, at best, misleading.
Thus, although no one really "forces" anyone to use anything, it is thanks to the users who have written and described a bunch of bugs that 3D koat is getting better. Again, the so-called "stable" versions are bugged no less than "beta" versions. Taking into account the fact that versions with glitches and errors were also uploaded to this branch, and these same versions were declared "stable", the user does not receive a full, working version of the program.
Therefore, due to the fact that ordinary users, including their error reports (and working in a program that, I repeat, was never 100% stable), made this program better, I believe that an update for such users should be free.
And as for the fact that it says "beta testing is voluntary", because the program, even in the stable version, often crashes for one reason or another. Thus, by paying money, you are not getting a 100% working product. And then there's also pay for the update.
This is strange and not logical.
In one version, something will work, but the other breaks, while in the version that was released six months later, something broken will be repaired and the working one will be broken. This is really the way things really are.
Thus, you are buying a supposedly working product that in fact has a lot of problems. Yes, there is an opportunity to return the money, but in this case, due to the fact that from version to version the stability of the program is either better or worse, it turns into something incomprehensible and inconvenient.
Sorry if my English distorts the meaning and seems rough somewhere, correct me or clarify what I mean.