The fact that you're speakine as if it's normal for everyone to do this might be pointing to how many people use physical mechs, which would come from the fact that it have been overpowered.
It's been a long time since I've worked on balancing the items for SM, but one thing I amed for were something called "perfect imabalance".
The basic concept is that you don't wan the perfect balance, because then it's possible to make the perfect strategy, or at least come pretty close to it. Combinging that with SM would lead it to be more a game of luck than anything else (that is, if everyone made the same mech).
You need some things that are overpowered in some situations, and some things that are overpowered in others. physical can be said to be overpowered trough doing way more damage than most other weapons, and often dealing damage to resistance as well when shooting. The downside being the bullet cost (and back in the days used to be range, but that has changed). Now you can say there have been added a second one with the resistance. But to explain how that is somewhat fair, we'll have to see why it's happening.
For it to be a viable strategy to rely on, there have to be A LOT of physical mechs compared to other mechs. And the truth is, there is. If you play in the top ranks, there is a lot. 5 out of the last 10 I've played have been physical (that's of course not a viable statistic, but an interesting note). Some mechs will certainsly lose to other types of mechs unless there is a large amount of luck. I bet we've all been in battles where we imadiatly see that this won't end well. If not, your mech is most likely overpowered.
What this update does is make people have to change up their tactics, which is good. SM is a game not only about strategy on the battlefield, but also in the workshop before the battle starts. People either adapt their physical build to the new reality, or they switch away from it. If enough people switch away from it, then there is no need to bring a physical reistance kit, you only got 2 slots, they have to be used well.
When all that is said, I'm guessing this is more a transgressional period mroe than anything else. Personally I've wasted a lot of kits simply because I had them laying around from what I got in boxes.
This update was to make people use the kits. It used to be a rare event, let's see if it stays that way or changes. Either way, it does force people to addapt to win, which is good.
Thank you Michael
Thank you developers
(^-check out the topics)