It is pretty complicated. And hard to explain.
It is not whether or not you compete but whether you can use the concepts of your system to function in a new environment. You say cant compete because you cannot use your entire skill set. Basically if you had to change invent or adapt on the fly you get stuck.
Basically your big issue is that you will get iinto a situation where you could go for an arm destruction and then not be able to work around that. And that is not very likley to even come up. let alone shift the fight.
lets compare an issue like that which is pretty minor to say a MMA fighter who competes and does not use his whole grappling arsenal. By in this case doing Muay Thai.
Which is pretty common.
Now we have had raised in this thread that some people struggle if they have not been trained specifically to fight on stairs or in a lift and so on.
That minor change to the unfamiliar snuffs them.
And i believe the reason someone hits this issue they are focused too much on the specifics. They get into an arm destruction opportunity and have to stall because they have practiced whatever and cant do that movement. It is an indication of training by route.
I have never encountered somone who has been winning a fight untill it gets to stairs and then loose due to some sort of shift. (And i have seen a lot of fights on stairs. and even some elevators)
So you have this issue. with arm destructions and whether or not you can choose them or another option. But it is not you alone who has this it. it is a trend I have noticed. people have to train in the gear they fight in. Or struggle to do 2 styles at once.
And I think it comes down to how you internalize your martial arts.