Your 1&2 disadvantage for bitcoin no be anything for long term investors because bitcoin price dey increase overtime and 1btc=1btc.
Some people fit go dey careless with their seed phrase or click on malicious links with malware wey go make them lose their coins. Self custody easy if you follow the simple ways to secure your funds. Greed again dey make many people go connect their wallet for random sites wey go drain their funds.
I think say this one dey the reason why some people no dey like buy bitcoin be that, I don ask many of my guys wey no dey buy bitcoin about the reason wey them no dey buy bitcoin and some of their answers na e be say them dey fear because them say any small mistake from bitcoin wallet address you don lost your bitcoin be that, some even say them wey no sabi anything about all this random link, if they go click any link wey Dey lost their bitcoin how them go do.
Some people no trust their self and that is why you go see many of our Nigeria people no too like bitcoin but if the hmm hear about the profit them go rush come and no be profit them dey use dey introduce person to bitcoin, so as I dey talk, our people dey fear to get scam because any small thing na e scammers dey use scam person.