Domains are in theory digital assets, so if you wanted to peg some kind of estimate, you probably can. From a net worth standpoint, not so sure if that's the right way to look at it
Crypto are also digital assets. If you own 1 Bitcoin, that may be counted towards your "estimated net worth". You can sell 1 Bitcoin today, so its something you can sell "now", unlike maybe in the future (if you go by the estimated value that you understand it to be, with the right buyer), like domains. I think that's one of the differences that make domains a different class of speculation, and that's quite a statement when you compare it to crypto, which is also incredibly speculative
Net worth is a grey area. You can look at an estimated portfolio value, if going by the price you can truly 100% sell it for "now" / in this moment, and not the "maybe future value" (if that makes sense), and in theory count it towards a net worth, but I think its a bit meaningless too (as
@inforg said). When you sell a domain on the spot for fiat (real money), you can then truly count that amount to an overall "net worth". IMO