Answering this question is quite simple, since it's rhetorical: without your own node, you're no longer really using Lightning, but only the illusion of Lightning across a company's infrastructure.

Using a Lightning custodial wallet means that the bitcoins technically belong to the company operating the node. You don't hold the private keys, and you don't control the channels. Your wallet balance is just a line in a service provider's database. This situation is certainly very convenient for beginners, and the user experience is often fluid, but the fundamental question is: what's the advantage of using Bitcoin and Lightning if you end up relinquishing the very aspects that set them apart from traditional currencies and banks?

Bitcoin's two main value propositions are monetary sovereignty (no longer depending on a central authority for issuing and holding) and censorship resistance (impossibility for a third party to prevent or filter payments). A custodial system on Lightning goes head-on against both these objectives: you can't check the platform's internal money supply, and by definition, an operator who holds all the funds and all the channels can censor, delay, prioritize or block your payments. Under these conditions, we can legitimately ask ourselves, what's the point of using bitcoin via Lightning if it's going to reproduce the same patterns of trust and dependency as with traditional state currency systems.

Philosophy aside, the more concrete disadvantages for you are as follows. Firstly, you have no way of verifying that the company actually holds the bitcoins corresponding to the balances displayed. It may operate on fractional reserve, be hacked, go bankrupt or simply disappear. In this case, you're just another creditor, with no real guarantee that you'll get your money back.

Secondly, the company is subject to regulatory risks: injunctions, freezing of funds, requests to block users or transactions, reinforced surveillance, or even outright prohibition of activity in certain jurisdictions. Every constraint that weighs on the service provider mechanically reflects on you.

In terms of confidentiality, the situation is no better. A custodial operator sees all your flows: amounts, frequencies, recipients, balances, spending habits. Combined with information provided by the application and possibly the underlying chain analysis on Bitcoin, this information can provide a very precise profile of your financial activity. Once again, it is a far cry from Bitcoin's aim of reducing financial monitoring.

The good news is that today, operating your own Lightning node is no longer the preserve of technical experts, as it may have been in the late 2010s. Relatively simple solutions are available for home users, which we'll explain in detail in the next chapter.