There's an ablative aspect to the Protomech resource debate. A Point of Protomechs can take down a Light Battlemech with each side taking roughly equal damage. But that damage killed the Battlemech, while 2 out of 5 Protos are still untouched an 1 has only armor damage. That means that the Point is still an operational force that can stay in the field and continue fighting in Trials. From the Clan point of view this might be seen as an advantage because you are spending resources to maintain a formation, rather than building an entirely new one. You would be sending in reinforcements to bring a unit back up to strength, rather than sending in an entirely new unit. (You're still replacing 5 points worth of strength, but its easier to handle when that's spread across several Stars.)
There's also the salvage aspect, were Protomechs don't have ammo explosions that destroy all equipment in a location. So it is very possible that Protomechs can be repaired primarily with salvage of downed Point mates, a big asset for a military that expects frequent but short term combat. Its much more effective to reclaim assets than it is to let them blow up when the ammo cooks off.