Yes it was smart because he's going to get a shìt ton of guaranteed money plus years of security.
NFL contracts can be front loaded with signing bonus money, roster bonuses, incentives & flat salary base. The per yer money almost doesn't really matter it's just how much of it is guaranteed & how much of it does he get upfront, because for a 10 year deal the majority of the money will be within the first 4 years of the contract & towards the backend will likely be a manageable base salary so that it doesn't eat it too much of the salary cap.
So they'll give him like 60-80% of his money within the first 4-5 years & the rest will be easy money. NFL teams don't want heavy Dead money contracts so they rarely ever backload a deal, they want to give you the money early & have you count towards the cap for less & less as the years of the deal dwindle down.
A 10 year deal in the league can ripped up & resctrured as soon as the guarantee money runs out, so if the league cap continues to rise & players get a larger percentage of the league revenue in collective bargaining, Mahomes can always just go back to the table & renegotiate a new deal.
But for right now, it's a great deal for Pat, he's going to be the highest paid player in league history.