I tried reasoning with the founder about how, as a build engineer, I find that highly disturbing, but they don't see any trouble with that.
Wouldn't recommend, for that reason alone. Tidelift may be a better option here.
Most libraries rarely need the kind of maintenance work that justifies paying people full-time on them. It's often the case that a library is written and then done - future development may be maintenance type work (supporting newer versions of whatever), or increased coverage of the library's use cases. For all this, Tidelift and Paydevs are a good fit.
But most projects that really need continuous chunks of money are going to be end user apps, adapters/sdks (i lied, those are libraries, but they're more visible and often against a moving target), web services, infra services, etc.
For those, I recommend taking more ownership of the finance and setting up sponsorships via Open Collective (https://opencollective.com/)
Source: I run my own open collectives, have corporate sponsorships through there, I've helped several OSS projects monetize, created my own successful open source startup, etc.
If you're an open source maintainer and need advice on this, feel free to email me and AMA (see profile)