It was, and AFAIK still is Scottish Parliament IT policy to use work issued laptops and iPads as Wifi hotspots when abroad. It's not an "attempted fraud", as Matheson himself asked SP IT to investigate the bill and clarify how, precisely, it came about before he submitted it as a standard working expense, and only did so after IT expressly instructed him to do so. I agree with you that to obfuscate the truth after it was known to him is an egregious act of stupidity, especially since the SIM being used was outdated and was supposed to have been replaced by that point, so yes, it is entirely his fault, and it is perfectly appropriate that he pays the expense from his own pocket.
What has become ridiculous is the insistence that Matheson somehow set out to "defraud" expenses, or that this was somehow a "grift". It's clear he made an extremely poor choice in an attempt to cover up his complicity, and for that he needs to be punished, but I do not accept that the sanction suggested by the committee is appropriate, given that it's on a par with the previous harshest sanction meted out to an MSP, and that was for sexually impropriety.
Perhaps a month suspension is appropriate for the offence, but then it's clear that there is a fundamental problem with regard to the strictures available if an "offence" of this nature is considered as serious as sexual misconduct. For that reason, John Swinney is absolutely correct to refuse to sanction it, because it's clear the furore surrounding this has been amplified by committee members determined to play petty politics with it.
Michael Matheson paid the 11k, eventually, and is facing suspension and loss of income. This has generated no end of fizzing and wailing, yet Michelle Donelan's Libel bill was over three times this amount, paid from public purse, and not a peep. The wailing and gnashing from Unionist politicians over this, while completely ignoring and refusing to acknowledge far more egregious cases of misconduct, theft, and criminality from members of their own parties just beggars belief, and Swinney is absolutely correct to tell them to get fucked.