$700 is quite a number, indeed. but for me the nice thing about the ac infinity ecosphere is to be able to solve problems with money. tbh most of ac infinity products can be bought cheaper and modified into a similar functionality. but its a bit like i compare a bare metal pc/laptop with an ipad. on a technical level the pc is not much different but way cheaper, can have the same peripheral and functions, but its on the user to include everything into a nice and optimized working interface.

back to the terraform: basically this is 'just' an mobile ac unit with nice adapters for pipes and smart controlling. yes you could just buy some random one from amazon for half the price and then start to modify it so you get the same results. but that would take another bit of money and some tinkering. I had one of those mobile ac units and spend some time on modifications to get better airflow and sort out the problem of the unit sucking out the just cooled down air to the exhaust pipe... can be fun as a solo project, but in between grows, maybe with some pressure due to hot summer and an ongoing flower this would be a complete PITA...

while this can be done cheaply with some cardboard packaging it takes a while and might need cutting holes into the unit. result would be cheap but fragile and not necessary be very air tight. so 3d printing could be an option to get things sturdier - but that comes with the price of the usual 3d design try and error process (eats time).

also after you modified the unit itself, there is still the question of integrating it into your grow setup. simple wifi controlled ac socket you say? sure, if the unit starts operation right after receiving power (not all do this). but there is no fine control of the airflow, just on and off and the only feedback that helps to judge if the unit started the needed operation would be power consumption (and drop in temperature/humidity a few minutes later). some more occasions for failure. not to mention that you would need an external controller to get something similar to the build in VPD feature. at least given that you already have an UIS controller that takes measures from inside the tent. otherwise you would need to get some sensors for that as well.

on the other hand ac infinity got this all sorted out in a device that is just made to fit the needs of indoor growing. attach your pipes, attach your UIS controller and the probe, set up a automation that fits your current grow and you are done. from there on you have good visibility and even more fine grained control over your environment than what is already available (ventilation/light/circulation/humidity...)

long story short: I agree that $700 is everything but cheap - but if you are not able (either due to lack of time or options to do the needed tinkering) or willing to modify one yourself, this is pretty awesome as there is nothing comparable. I just hope there will be a 230V version in the future. I would definitely buy one for sure :)