Yes, one of the reasons for the two week cap on MRR is to prevent people from overpromising (scamming) people. There is a reputation system in place as well so sellers who do not deliver as promised get bad rating and below a certain limit are barred from advertising their services.
This way a customer gets what they paid for under no illusions and there is no incentive to over-promise and under-deliver on the part of hardware owner-operators.
Another reason is that it creates a fair and free market. One of the biggest criticisms of cloud mining is they lock you into a year long contract in a field where things are constantly changing.
Mining a crypto currency which gets popular and whose price rises means that in order to keep getting the same amount of coins you have to increase your mining power or be ok with diminishing returns.
With a two week limit this allows the end-user to adjust their hash power purchase as they see fit or stop mining altogether if it is no longer profitable.
And from a hardware owner-operator/miner/hash provider like myself it allows us to price our mining capabilities based on customer demand and available supply.
The customer gets to know exactly what hardware is being used and can make the decision whether to rent it or try to buy it to mine on their own.
There are no secrets.
By contrast, most cloudmining companies will never tell you exactly what hardware they are using and how much capacity they have.
MRR and Nicehash present an alternative: fair and free market where everyone knows upfront what to expect and can plan accordingly under no false illusions.
Cloudmining on the other hand is a closed market, often using flashy ads and paid shills (often other customers are given promo codes to spam) to convince new people to sign up and buy in on these long contracts which, (due to the difficulty increase I mentioned earlier), they seldom if ever will see an return of investment on.
Some of the less credible cloudmining companies will even use misleading advertising which leads people to believe they will receive a certain number of coins per day, week or month for the length of the contract despite the realities of mining against increasing difficulty.
When they come up short they will often ask a customer to "buy just a little bit more power" to keep the same amount of coins coming.
Still others have no mining hardware at all and are nothing more than MLM ponzi schemes.
So the two week limit is to keep both sides honest and the whole process transparent.
These are worth a watch: