TL;DR - One latency request per second accounts for less than 0.05% of CPU per second and 0.117% of bandwidth which will in no way harm game performance.
As I stated, I agree with you that it is "'optimal' to check latency when a 'more purposeful' request is made".
You asked though, "How will this help the game by adding more requests?"
My first post addressed a couple of useful scenarios while my second addressed how it doesn't hurt the game in terms of processing performance. I admit I did not address it in terms of bandwidth though. No where did you nor I mention the "cause of latency". That's not what this is about unless you are suggesting that adding a check for latency adds additional latency. Is that what you're saying?
In terms of the target network usage, to be accurate, its 50 KBps (180 MB/hr) not 50 kbps (22.5 MB/hr).
So I went ahead and did a light "visual" profile of the network stats within Studio's View tab. In an empty place with a single player without the Latency Monitor, Roblox server averages 0.07 KB/s out and 0.07 KB/s in. In the same empty place with a single player with the Latency Monitor running, the averages are 0.09 KB/s out and 0.11 KB/s in. This suggests about a 60 byte overall payload to send the RemoteFunction:ClientInvoke() with no parameters and receive a single number value back. I could go further and use a network analyzer such as WireShark to analyze the actual protocol-level packets being sent but it already doesn't seem to be worth the effort. 60 bytes / 50 KB (50 x 1024 bytes) = 0.117% of target bandwidth.
I won't argue the average bandwidth of Roblox games as I don't know that figure, however, I will say that there is MUCH that can and should be done to keep bandwidth usage low.
Realistically speaking, the primary thing that concerns me about Roblox and it's network usage (with respect to FilteringEnabled being on) is Instance and respective physics replications from the workspace. This design model, building out the game world in the server's workspace and it being replicated to players automatically, is a primary reason why development on Roblox is so "easy". However, it's far from optimal from a networking or large/complex game perspective.
This is NOT the way typical PC/console/mobile online games work. Typically, the vast majority of assets and the physics engine will exist almost entirely on the client. The server would be responsible for replicating position, orientation, transformation, physics input data and events for overall assets between clients not each granular primitive that makes up the asset. This can be done in Roblox too but is a more complex approach using local parts/models and handling the replication yourself. However, unfortunately, even with FE, the client will still attempt to send physics updates to the server although the server won't even accept the packets according to my tests.
That said, very few games (even games like WoW, Battlefield, Halo, FIFA, Minecraft, etc) reach 50 KB/s of bandwidth.
Ultimately though, speculative arguments won't get anyone anywhere. Actual profiling is where the truth lies. And so far, my point still stands... One latency request per second accounts for less than 0.05% of CPU per second and 0.117% of bandwidth which will in no way harm game performance.
Some casual, unscientific reading: https://www.rhoonet.com/how-much-data-does-online-gaming-use/