Particle Board less than 1/2" thickness may not take big load, but again it depends on which Brand of Particle board they are using, its density and bonding chemical. That can be ensured only if we are building the boxes on our own.
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Second point is the method of joining. Joining method is having larger impact on life of the furniture and whether it is subject to movements.
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These particular products are meant for online sales and easy to transport. As such these will come in pieces wherein the buyer has to assemble with the fasteners they have provided. It would be a easy way of joining, keeping in mind the common people, non-techies and no need of tools except a screw driver or an Allen key provided along with the set. So, naturally this can not be strong and long lasting joints. But good for make-shift like of things. The main factor for choosing it for aesthetics and as a readymade solution. It again depends on the buyer, durability he is looking after and the purpose.
IMO better to build own cabinet with selected plywood, finishing and fastening method with the help of carpenter, particularly if it is Wall mount for Vinyl storage.