If you are approaching and have room but someone is closing the gap, it may indeed be safer to speed up so you can take the spot before it closes and you are forced to stop
Granted, drivers should not be taking away the room you need to merge, but if everyone on the road were good drivers then we might not be seeking such nannying tech built into our cars to force them to drive better
If the computer enforced max speed is 120km, and I'm going 120km, and the vehicle coming up is also going 120km, they can't overtake you, they can't close the gap.
Maybe, if the vehicle ahead of both of you is going much slower than either of you then yeah, they could close the gap. But even in that situation you could speed up to the max speed, matching that of the approaching vehicle, and merge. You'd still need to slow down to match the vehicle ahead, but so too would the one behind you, regardless of what you were going to do.
This won't happen unless it becomes illegal to drive un-limited vehicles entirely though
People will drive older un-limited vehicles, or import un-limited cars from elsewhere, or buy limited cars and jailbreak them...
You're starting with a flawed premise and then concluding what you prefer
Some guy is shutting you out of the lane next to you, slow down and merge behind them.