Lower limits make no sense if you stick to it as a set in stone rule, but I think the issue is that there are not very good opportunities to invest amounts that are as low as $10. You would want a reputable exchange with as low as withdrawal fees as possible. The problem is the management of those low amounts taking into account network fees. If someone invests like $5 per week and then has 4 withdrawals a month and 4 inputs, it is not the best strategy to go about investing.

There is a spot when saving for a month gives you less frequent exposure, but saves on fees and risk. Sometimes you got withdrawal minimums as well, which means you would have to find an exchange that has no minimums, very low withdrawal fees and then you would still have a lot of inputs if done on a weekly basis.

If somebody says that they fear not being able to manage saving for a month and then rather do a $20 or $40 investment instead of smaller amounts weekly, well then bitcoin is a tough investment anyway and it does require patience and consistency an definitely the ability to resist volatility and early sales.

The issue is the whole process. I think finding a place to buy bitcoin is possible, but that is not the last step if they want to get their investment right. You will want control over it and this is where it becomes complicated with very small amounts.