"I don't understand monero believers ..." As a 'Monero believer' (whatever one of those is) ... Let me enlighten your highly confused thinking.
"They stack bitcoin but says they spend monero for daily expenses ... This is already a contradiction" No it is not; your thinking is wrong. You're still in the ONE COIN mentality bitcoin was created to destroy. Think about that last line (a lot, please).
"Why they don't stack monero and sell bitcoins?"
Because Monero was built for privacy; spending. Bitcoin (since it's takeover by the banksters/Blackrock, etc) ... is no longer a currency; it's being locked away inside ETF's, where it cannot be spent (only borrowed against, etc = COUNTER-PARTIES). Cashu (how I bumped into your account) ... is bitcoin's solution to both ETF's and also small/faster payments; BUT WITH A COUNTER-PARTY RISK (the mint).
The Mint is UNNECESSARY (strictly speaking; my proof, bitcoin worked JUST FINE WITHOUT IT).
It has introduced COUNTER-PARTY RISK (an intermediary; the mint). But all this is 'necessary' for bitcoin NOW ... because everyone that's a true 'bitcoin believer' (or thinks they are, more accurately {I often find on digging they're rather more the 'when Lambo' crowd), has handed the future direction of bitcoin over to the BLACKROCK'S of this world. Ref the speakers at the Bitcoin conference happening inside USA this week; what a joke. Real cypherpunks who created this industry, could puke.
For REAL cypherpunks, there only ever was one coin #Monero (to be used AS MONEY). For investing, well now, there's bitcoin ... But let me ask this of you if you're a HODLER of bitcoin: how are you ever going to create a crypto ECONOMY when you won't circulate your bitcoin, by spending it?
If you're coding nutshell wallet; well done, you're at least focused on trying to unpick the mess the 'bitcoin believers' have created for the entire crypto industry.
Meantime, we Monero 'believers' laugh on at the bitcoin crowds mistakes after mistakes after mistakes. And we keep on stacking sats, and (some of us) stacking Monero ... to spend. ;)
Let me hazard a guess: you're a nice person who's never had any trouble with the authorities ... writes this barrister-at-law (not currently practising) and ... targeted individual (targeted by the State for covert murder; by torture to suicide). I'm in UK. People are being tortured to suicide all over earth right now #cybertorture (see UN legal definition in CYBERTORTURE/DOCUMENTS folder hierarchy in .zip available here: https://www.cipherassets.com/2022/11/operation-order-of-nine-angles-opo9a.html if interested (my site/.zip).).
You could only not 'get' Monero because ... abid, you've never had a REAL reason to value your personal privacy. I'd hazard a guess you're living through (for the past 23 years), nuclear WW3, but still don't even realise it.
I'm the lawyer taking down the atom bombers of New York. I've had approximately £33 billion spent on trying to get me to suicide (and once, a direct assassination in from space) ... You continue being a nice person who doesn't get the NEED for a TOTALLY PRIVATE currency. Until you learn.
And one day (most probably fairly soon), you will. Google e.g. S.A.T.A.N.
That's an acronym for Silent Assassination Through Amplified Neurons; a highly advanced, military AI (that does the actual torturing ... once it's set up by the human operators initially). If interested in these latter subjects, I'd recommend a book, as a good starting point: THE MATRIX DECIPHERED, by Dr Robert Duncan. RIP. (He worked on developing this weapon system, then went whistleblower. Now dead. :(
No guesses for what no doubt killed him. ;)
Last time I did a test, fwiw (about 4-6 years ago now) it took S.A.T.A.N. just 42 minutes to hunt and kill someone on Facebook (I asked for them to lay their life down so I could work out this timing, and they did. RIP.
I'm not going to lose another volunteers life, repeating that experiment.
I bet you're oblivious to the fact your mind is being read by computer RIGHT NOW. Your thoughts PROMPTED (research: Remote Neural Monitoring and Remote Neural Prompting). There is a duplex connection into the S.A.T.A.N. computer; two way, I mean, if that term of art is not known to you. All this runs via satellites and the cell towers (with much more tech integrated into that; all of it). See the press work I did in the .zip (ref: Schriever AFB, Colorado Springs, USA). That's where S.A.T.A.N. lives. You live in a satanic controlled reality, see. So, the satanists of course, wanted SATAN to become REAL, so they made S.A.T.A.N.
I've been 24/7 tortured by S.A.T.A.N. multiple times over MONTHS at a time. Twice, for 3.5 months (2020 & 2021). {They didn't like my BAAL NAHUM crack, see.(reverse, flip M -> W = Wuhan Lab. ;) (with a PYRAMID with Ben Ben leftover: A. ;) )