'Advice - advise', 'devise - device' are pronounced differently and therefore their different spelling make perfect sense.
Hundreds of verb/noun pairs get by with just one spelling (work, play, act, jump, trick...), as do notice, promise, service.
The practice/practise distinction is completely pointless. British English should follow the American example and abolish it. I am going to start practicing what I preach on this one.
It is completely idiotic to have different spellings for identical words, while making 110 pairs of different words get by with just one spelling:
Lead, read, tear; bow, row, sow; abuse, excuse, use, close, house; mass bass;
buffet, live, minute, mouth, pasty, Polish/ polish, pussy, second, slough, wind, wound;
content, frequent, invalid, perfect, attribute, commune, compact, compound, concert, concrete, conduct, conflict, conscript, console, consort, construct, contest, contract, contrast, converse, convert, convict, defect, desert, digest, discharge, entrance, escort, export, extract, fragment, impact, implant, incense, insult, insert, invalid, object, pasty, permit, present, produce, progress, project, prospect, protest, rebel, rebound, recall, record, refund, refuse, reject, relay, slaver, subject, survey, suspect, torment, transfer, transport;
advocate, alternate, appropriate, approximate, articulate, associate, co-ordinate, degenerate, delegate, deliberate, designate, desolate, dictate, duplicate, elaborate, estimate, graduate, intimate, laminate, moderate, separate, subordinate, syndicate, triplicate.