More than the absolute measure, I think the growth it is important.
Matt Odell, the lovable curmudgeonly idealist and privacy buff is making some fairly good criticisms of this stat. And I think he has a great argument as far as the land of perfect goes. I have long been the Bitcoin Fundamental Iconoclast (not even counting my interest in Monero) because of my nuanced opinion on "Be your own bank™" as an ideal. It is just not possible. There are too many of us. There are too many who are technically challenged. Not to mention being your own bank is risky as hell.
The error, in my opinion is the idealistic thought that because Bitcoin removes the absolute NEED for a trusted third party that we should only build structures that also eliminate that need. But the nuance is that we have the choice. To employ however little or however much trust we want in whatever scenario. Having a "bank", which is what WoS really is, is a helpful bit of trust for many. The UX is better with WoS, no one has to run a node, or even worry about using a compromise wallet like Muun, Breez or Phoenix etc which generally have less smooth user experience.
On the other hand Odell is right. WoS is a huge target for the powers that be, thieves and accidents. And essentially an unregulated bank that could steal all the funds whenever they want without any help from any governments at all. So my 20k sats I have in there are a risk.
But therein lies my nuanced answer to the problem. WoS is truly a WALLET. In the sense that I am not usually going to be walking around with $20k USD stuffed into one of my back pockets for a night on the town, I am also not going to carry much cash in my WoS. I have already decided, that if I were to visit El Salvador, for example, I would likely load up two (perhaps three) lightning wallets. I would use Zeus with some funds on and off chain, enough for the trip. But I would also have WoS with maybe $100 in it at any time for using when we are out buying pupusas, coffee and renting boogie boards. If using Zeus worked well enough? Well, I could just use that. But if not, I would be glad enough to have WoS work for fast, cheap, trouble free payments. Perhaps if I were feeling adventurous I would try a middle road like Muun as well.
But this is notable in my opinion because it istrue for someone with reasonable skills at "being his own bank". Even in spite of that I would want to make certain compromises to my mix of convenience and sovereignty. In fact that is part of what sovereignty is. The ability to control ones own destiny and decisions.
So people using Wallet of Satoshi as a BANK ACCOUNT are making a big mistake. And perhaps that is the meat of Matt's argument. That folks in El Salvador and Africa using it as their primary financial storage system are at risk of the eventual rug pull... Me losing $100 on vacation? Not exactly the best thing to happen in a day... but a person in Nigeria losing most of their savings? Kinda a different ballgame.
One last though before some grump I have on ignore takes up his usual canard. ALL of these statements are ABSOLUTELY as true with BTC on the base layer as they are with lightning. The Lightning part just adds some spice to the meal, so to speak...
I also think this stuff gets sorted out over time... but it might take a while.