A HMMVW equipped with four LOSAT missiles isn't particularly mobile or capable of offensive operations!

The thing about LOSAT is that it's designed for considerable overmatch - it's the conceptual equivalent of firing a Tomahawk at an MG in a window. It'll kill your target, no problem, but it's rather too much - and that comes at the cost of ammunition capacity, mobility and, well, cost. The missiles are huge. In terms of battlefield utility, even if it can kill four tanks per reload, that doesn't compare to the offensive potential of an armed and armoured bundle capable of cross-country rapid mobility, engaging targets on the move, equipped with sensors to pick out enemy vehicles long before they pick it out. That is to say - there're many things that can destroy a tank, but not many things that can do the vital job of a tank nonetheless.

CKEM is a slightly more practical concept (to be honest, LOSAT was probably more an excuse to look into dual-use technology with applicability in the realm of terminal stage KE interceptors in missile defence systems), but even then, it's a big, kinetic energy munition that requires LOS to be usable - as the difficulties had with MRM-KE show, N/BLOS KE is a much more difficult prospect.

Which means that, put against systems like Tamuz/Spike NLOS, the key difference is this - do you want to bet on your HMMVW spotting and engaging a tank, comfortable and equipped with sensors, computers and weapons for LOS superiority, first and successfully, or would you rather sit your lightly armoured missile carrier 25km back and use your superior network and sensor environment to top-kill them from beyond their line of sight?