Licensing Requirements for purchasing use Maschine Studio.

You already have licence for Studio, MK3 and M+. You could install Maschine and Komplete Select on nine computers (3x3 computers).

If you do not need more (3 more computers), Studio without SW will do perfectly....

Generally, I never have had problems with transferring SW licences when buying NI controllers/keyboards. And I have already bought six of them over the time... So, the problems are not so frequent as it might seem. And also one may avoid it, if you know, that seller should provide you with Licence Transfer Code.

Generally, HW sold without bundled SW tends to be cheaper.

There is another aspect. Sellers did not want to transfer bundled SW in situation when they had upgrades on that SW. NI has changed things few years ago. In most cases (I do not know if it applies to Studio) if HW is transferred, bundled SW stays at seller's account and buyer gets completely new licences. So that, there is no reason not to do the transfer correctly. (Unless it is stolen or found-lost item and seller cannot ask NI for HW transfer. Or the original owner passed away and it would be difficult...)

Shortly, in your case, no problem with buying Studio without SW. Still, it is better to buy it in correct way including HW Transfer - that makes you sure it is not stolen/lost-found item.