Limits
For Neteller, my limit is theoretically 150,000, however this is NOT credit, but is money that has to be there in the first place.
Where credit is involved, the limits on cards is lower. Entry level seems around 500 per card per week, going up to around 1400 per card per week for VIP levels. Some limit on transaction size, say 280, but do not appear to have an overall limit, relying on the card issuer to impose one.
Some casinos run a "deposit and wager once per point" type of tournament. Having a webwallet with no real limit can be pretty useful on St Patrick's day. If enough funds can be rounded up, it is throughput, not amount wagered that counts. I am now gathering funds for this purely hypothetical St Patrick's day tournament that may have a theoretical top prize of $2500. I plan to make the top 5, and will be seriously embarrassed if I fail to get listed in the top 10, as I won this tournament last year!
It should be remembered that depositing 10,000 all at once, and wagering it once, does not mean 10,000 lost, most of it can be withdrawn and the tournament points earned (200 in theory). Players that have limits must wager for $500(500) payouts (25 points each, was 10 last year), a far more dangerous strategy as Blackjack does not count!
The main way an out of control player can come to grief is having a high limit by combining several cards over several casinos. It is possible to lose a great deal of money that does not actually exist for the player. With a webwallet, money lost is money the player already has, and they have the option to call it a day without owing any more.